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Biomedical subjects

A T Chan

Publications and source records attributed to A T Chan.

At least 19 recordsLinked to original sources
PubMed2006

Cyclin D1 A870G polymorphism and the risk of colorectal cancer and adenoma.

Cyclin D1 (CCND1) plays a key role in cell cycle control, particularly in the transition from G1 to S phase, which is regulated by cyclin-dependent kinases. A common adenine to guanine polymorphism (A870G) in the CCND1 gene has been associated with a longer-life protein and an increased risk of colorectal cancer and adenoma in some studies. Among subjects with hereditary nonpolyposis colorectal cancer, the A870G polymorphism has also been associated with a younger age of onset of colorectal cancer. We analysed 181 colorectal cancer cases and 475 matched controls and 524 adenoma cases and 517 matched controls within women in the Nurses' Health Study (NHS) cohort, 171 colorectal cancer cases and 347 matched controls and 372 adenoma cases and 712 matched controls nested within men in the Health Professionals' Follow-Up Study (HPFS) cohort, and 258 colorectal cancer cases and 415 matched controls within men in the Physicians' Health Study (PHS) cohort to assess the risk associated with the CCND1 A870G genotype. Moreover, we assessed whether CCND1 genotype modified the effect of a sporadic (nonsyndromic) family history of colorectal cancer as well as the effect of other dietary and lifestyle risk factors for colorectal cancer and adenoma. In all cohorts combined, the CCND1 polymorphism did not show statistically significant associations to risk of colorectal cancer (odds ratio (OR) for A allele carriers, 1.04; 95% confidence interval (95% CI), 0.82-1.32) or adenoma (OR, 0.96; 95% CI, 0.79-1.18). The CCND1 A870G genotype was associated with a modest, although nonsignificantly elevated risk of colorectal cancer (OR, 1.59; 95% CI, 0.98-2.57) in women. In contrast, the polymorphism was not associated with increased risk of adenoma in either men or women. Among participants with the A870G genotype, a family history of colorectal cancer conferred a substantially greater risk of colorectal cancer in the women (P for interaction=0.06) and adenoma in the men (P for interaction=0.02). Current postmenopausal hormone (PMH) use was associated with a significant reduction in the risk of colorectal cancer and adenoma among women with the A870G genotype, whereas there was no effect of PMH use among those with the GG genotype. The CCND1 polymorphism appeared to confer a modest elevation in the risk of colorectal cancer among women. Moreover, the A870G genotype may enhance the protective effect of postmenopausal oestrogen use on the development of colorectal neoplasia.

Adenoma↗
PubMed2006

The role of biologic therapies in the management of systemic vasculitis.

The recent development of biologic therapies capable of selectively targeting components of the immune system has revolutionised the treatment of inflammatory arthritides. The steady increase in use of biologic agents coupled with the expansion in the knowledge of the pathogenesis of vascular inflammation has led to their application in the treatment of primary systemic vasculitis. These agents may have a role in addition to or in place of conventional immunosuppression and also be effective when the latter fails to induce remission. The use of biologics as targeted therapies has also, in reverse, improved our understanding of the pathophysiology of vascular inflammation. While the advent of biologics heralds a new era in the management of the systemic vasculitis, evidence for their efficacy is still in its infancy and has yet to match that of conventional immunosuppressants. In this review, we examine the up-to-date evidence for the use of biologics in systemic vasculitis, including TNF-alpha inhibitors, and highlight the challenges facing their use. We examine the rationale for using biologics based on the pathophysiology of vasculitis. Issues of toxicity and pharmacovigilance with the use of biologics are also discussed. Finally, future directions and predictions are presented.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2005

Expansion and enhanced survival of natural killer cells expressing the killer immunoglobulin-like receptor KIR3DL2 in spondylarthritis.

OBJECTIVE: The spondylarthritides (SpA) are strongly associated with possession of HLA-B27. We hypothesized that the expression of abnormal forms of HLA-B27 in SpA may have a pathogenic role through interaction with cells bearing natural killer (NK) receptors, in particular, killer immunoglobulin-like receptor (KIR) KIR3DL2, a receptor for HLA-B27 homodimer (B27(2)). We therefore undertook the present study to determine the number and function of NK and T cells bearing KIR3DL2 in SpA. METHODS: Expression of KIR3DL2 on NK and T cells was quantified in peripheral blood (PB) from 35 patients with SpA and 5 patients with juvenile enthesitis-related arthritis (juvenile ERA); samples were compared with samples from healthy and rheumatoid arthritis (RA) controls. Paired synovial fluid (SF) was studied where available. Expression of other KIRs as well as activation, memory, and homing markers on KIR3DL2+ NK and T cells was quantified. NK cell survival was assessed using the apoptotic markers annexin V and 7-aminoactinomycin D, and cytotoxicity by (51)Cr release assay. RESULTS: In SpA, an increased number of PB and SF NK and CD4+ T cells expressed the KIR3DL2 receptor compared with controls. In ERA, KIR3DL2 expression was increased in PB and SF CD4 T cells (and SF NK cells) compared with RA controls. KIR3DL2+ NK cells had an activated phenotype, and were protected from apoptosis by culture with a cell line expressing B27(2). SpA PB mononuclear NK cells from SpA patients showed greater cytotoxicity than those from controls. CONCLUSION: KIR3DL2 expression on NK cells and CD4 lymphocytes is increased in SpA and ERA. These cells are activated and may have a pathogenic role.

Adolescent↗
PubMed2002

Prevalence of snoring and sleep-disordered breathing in a group of commercial bus drivers in Hong Kong.

OBJECTIVES: To assess the prevalence of sleep-disordered breathing (SDB) and its associated symptoms in a group of commercial bus drivers in Hong Kong. METHODS: Two hundred and sixteen of 410 bus drivers from three different shifts were interviewed with the Sleep & Health Questionnaire (SHQ) and the Epworth sleepiness scale (ESS) at a Hong Kong bus depot. Seventeen subjects from each shift were then randomly selected for at-home sleep study using the Mesam IV device (Madaus Medizin-Elektronik, Freiburg, Germany). RESULTS: There were 207 men and nine women (mean age 42.4 +/- 7.5 years; body mass index (BMI) 25.4 +/- 4.5 kg/m2; ESS 5.3 +/- 4.2). From the SHQ it was discovered that: (i) daytime sleepiness was reported by 87 subjects (40%), (ii) snoring > or = 3 times per week was reported by 80 subjects (37%), (iii) witnessed apnoea was reported by 17 subjects (7.9%) and (iv) 29 subjects (13.4%) reported having fallen asleep during driving. Among the 51 subjects who underwent the at-home sleep study: (i) 31 subjects (61%) had respiratory disturbance index (RDI) > or = 5 per hour of sleep, (ii) 21 subjects (41%) had RDI > or = 10 per hour of sleep, (iii) 12 subjects (24%) had RDI > or = 15 per hour of sleep and (iv) 35 subjects (68.6%) snored objectively > or = 10% of the night. Ten subjects (20%) had RDI > or = 5 and sleepiness at work, while five subjects (9.8%) had RDI > or = 5 and ESS > 10. No significant differences were noted in the SHQ responses, ESS, objective snoring or RDI among the three groups. Multiple regression analysis showed that BMI and witnessed apnoea were the only positive independent predictors of RDI. CONCLUSIONS: This study showed a high prevalence of objective snoring and SDB in a group of commercial bus drivers. Neither self-reported sleepiness nor the ESS could identify subjects with SDB.

Adult↗
PubMed2001

Pharmacokinetic study of intralesional cisplatin for the treatment of hepatocellular carcinoma.

BACKGROUND: In the current study the authors examined the pharmacokinetics of direct intralesional injection of cisplatin/epinephrine/bovine collagen gel in patients with hepatocellular carcinoma and cirrhosis. METHODS: Six patients with cirrhosis and unresectable hepatocellular carcinoma received a direct intralesional injection (range, 6.7-26.7 mg) into their tumors under ultrasonographic guidance. The authors determined the total cisplatin (Pt) concentration in the plasma and urine and nonprotein-bound free Pt in plasma ultrafiltrate using flameless atomic absorption spectrometry. Data from individual patients were analyzed to calculate the pharmacokinetic parameters via a noncompartmental method for constant infusion. To demonstrate that the changes in pharmacokinetics are not related to the underlying cirrhosis, a similar methodology was applied to measure the pharmacokinetic parameters of four similar patients who were treated with cisplatin, 75 mg/m(2), as a 1-hour intravenous infusion. RESULTS: The time to attain maximum concentration of total Pt after intralesional injection was dose-dependent and ranged from 2-13 hours. The concentration-time curve was biphasic in nature. The initial half-life of total Pt in patients who received an intralesional injection varied with the cisplatin dose. The initial half-life for cisplatin doses < 15 mg was approximately 9 hours and the initial half-life at higher cisplatin doses (> 15 mg) was approximately 25 hours. The area under the curve (AUC) was dose-dependent with values ranging from 38-150 microm/mL x hour. Pharmacokinetic parameters for free Pt (ultrafiltrate) were significantly different. The time to attain maximum concentration (t-max) and terminal half-life were shorter and the average AUC was approximately 100-fold lower than total Pt. After the intravenous infusion of cisplatin, the t-max for total and free Pt was 1.3 hours and 1.1 hours, respectively. The terminal half-life and average AUC for total Pt was 194 hours and 247 microg/mL per hour, respectively, and its corresponding parameters for free Pt after intravenous infusion were much lower, similar to the findings for the intralesional injection. CONCLUSIONS: The prolonged t-max and initial half-life noted with the intralesional injection of cisplatin/epinephrine/collagen gel are consistent with its proclaimed ability to retain cisplatin at the tumor and delay its release in systemic circulation. The kinetics of intralesional cisplatin injection also suggest local sequestration of the drug in the injected site. Parameters of intravenous cisplatin infusion in cirrhotic patients are similar to those of patients from the historic control group.

Aged↗
PubMed2001

Quantitative relationship of the circulating tumor burden assessed by reverse transcription-polymerase chain reaction for cytokeratin 19 mRNA in peripheral blood of colorectal cancer patients with Dukes' stage, serum carcinoembryonic antigen level and tumor progression.

We prospectively analyzed the circulating tumor burden in colorectal cancer patients using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) for carcinoembryonic antigen (CEA) and cytokeratin 19 (CK19 ). We distinguished the mRNA levels in peripheral blood between 33 patients and 26 healthy controls with reference to SK-BR-3 cell line. We found CEA-mRNA in 88% of patients and 92% of controls, and CK19 mRNA in 64% of patients and 19% of controls. Our CK19 mRNA assay was sufficiently sensitive to detect one SK-BR-3 cell among 10(6) normal blood cells. The upper limit of CK19 mRNA among controls was exceeded by 14 patients, and 12 patients (86%) developed systemic metastases/recurrence. Significantly elevated CK19 mRNA levels appeared to originate from circulating malignant cells (P<0.0001). Of relevance, the CK19 mRNA level increased with advancing Dukes' stage and correlated directly with the serum CEA level (P=0.016). CK19 mRNA quantification may prove valuable for cancer staging and disease monitoring.

Adult↗
PubMed2001

Dextran reduces embolic signals after carotid endarterectomy.

One hundred fifty patients undergoing carotid endarterectomy were randomly assigned to receive intravenous 10% dextran 40 or placebo. Transcranial Doppler monitoring of the ipsilateral middle cerebral artery 0 to 1 hour postoperatively detected embolic signals in 57% of placebo and 42% of dextran patients, with overall embolic signal counts 46% less for dextran (p = 0.052). Two to 3 hours postoperatively, embolic signals were present in 45% of placebo and 27% of dextran patients, with embolic signal counts 64% less for dextran (p = 0.040). We conclude that dextran reduces embolic signals within 3 hours of CEA.

Aged↗
PubMed2001

The use of brush cytology and directed biopsies for the detection of nasopharyngeal carcinoma and precursor lesions.

BACKGROUND: It has been proposed that nasopharyngeal carcinoma (NPC) has an early noninvasive stage, designated nasopharyngeal intraepithelial neoplasia (NPIN). Hence, the detection and treatment of NPIN will prevent NPC from developing, and this would be similar to the strategies used for cervical cancer prevention. We wanted to ascertain the feasibility of using a brush sampler to collect cells for the cytologic diagnosis of NPIN and NPC. If successful, the technique could be used as a screening test in endemic areas. METHODS: A disposable sampler (Uterobrush) was used to collect nasopharyngeal mucosal brushings from 546 patients for cytologic examination. After this, most patients had biopsies, and this allowed histologic-cytologic correlation to be undertaken. RESULTS: In 528 patients (96.7%) there were satisfactory cytologic and biopsy specimens for evaluation. There were 149 cases with positive histology and 103 had positive cytology (specificity was 100% and the sensitivity was 69.1%). One case of NPC with concurrent NPIN was seen among the biopsy specimens, but no case of NPIN was detected cytologically. CONCLUSIONS: The cytologic pickup of NPC was substantially lower than that obtained on biopsy. More importantly, NPIN was uncommon. Therefore, a screening test that depends on the collection of cells for the microscopic diagnosis of NPIN and NPC is unlikely to have a major impact on the incidence of NPC. Furthermore, obtaining a good cytologic specimen from the nasopharynx is not simple, and this further limits this technique for mass screening purposes. The concept of a cytologic test for NPC, similar to the Pap test for the prevention of uterine cervix cancer, has still to be realized.

Adult↗
PubMed2001

Application of classification tree and neural network algorithms to the identification of serological liver marker profiles for the diagnosis of hepatocellular carcinoma.

OBJECTIVE: Although many attempts have been made to identify tumour-specific alpha-fetoprotein (AFP) glycoforms or other serological markers for the diagnosis of hepatocellular carcinoma (HCC), none of the available markers has, so far, shown satisfactory sensitivity and specificity. Here we aimed to apply classification tree and neural network algorithms to interpret the levels of multiple serological liver markers to improve overall specificity and sensitivity, particularly with a view to discriminating between liver cirrhosis with and without HCC. METHODS: We developed classification trees and neural networks that identified serological liver marker profiles comprising AFP, alpha1-antitrypsin (A1AT), alpha2-macroglobulin (A2MG), thyroxine-binding globulin (TBG), transferrin and albumin as well as sex and age, which might permit the diagnosis of HCC. Data were collected from 65 HCC patients, 51 patients with liver cirrhosis alone (LC) and 51 normal healthy subjects. RESULTS: The generated classification trees and neural networks showed similar diagnostic values in differentiating HCC from LC. The classification trees identified AFP, A1AT and albumin as the most important classification parameters, whereas the neural networks identified A2MG, AFP, A1AT and albumin as the predominant factors. The classification logic of the classification trees indicated that more HCC cases could be identified among cases with slightly elevated AFP levels by using the serum levels of A1AT and albumin. The neural networks were also useful for the identification of the HCC cases when the AFP levels were below 500 ng/ml (p < 0.005). The neural networks could identify HCC cases with AFP levels within the normal range, but the classification trees could not. By combining the conventional AFP test and the neural networks, the overall diagnostic sensitivity for HCC was significantly increased from 60.0 to 73.8% (p < 0.05) while maintaining a high specificity (88.2%). The sensitivities for tumors of different sizes were similar. CONCLUSION: The neural network algorithm appeared to be more powerful than the classification tree algorithm in the identification of the distinctive serological liver marker profiles for the diagnosis of the HCC subgroup without significant elevation in serum AFP levels. By incorporating serological levels of other liver markers and including data from a large number of patients and control subjects, it should prove possible to develop a versatile neural network for early diagnosis of HCC.

Adult↗
PubMed2001

The cost of palliative care for hepatocellular carcinoma in Hong Kong.

BACKGROUND: Hepatocellular carcinoma (HCC) is endemic in parts of Asia and Africa and most patients are not suitable for treatment with a curative approach. Little is known about the cost of palliative care for HCC. OBJECTIVE: To determine: (i) patient-specific costs of palliative care of HCC; and (ii) individual factors that drive patient-specific costs and to develop a model of cost per case under alternative circumstances. METHODS: 204 patients with inoperable HCC were prospectively tracked from first hospitalisation until death for health service utilisation. A societal perspective of cost was taken, including costs of formal and informal services incurred by payers, caregivers and patients. Observational data from a large Hong Kong cancer care programme were used. A regression analysis was performed using formal costs only, with the cost per observed day as the dependent variable. RESULTS: The median survival was 95 days and the mean observation period was 153 days. The mean value per person for formal healthcare cost was 30 983 Hong Kong dollars [$HK] ($US3872, 1998 values). The distribution of cost values were positively skewed. The regression analysis showed that age, days of observation and survival were negatively related to cost per observed day, and the Child-Pugh grading of severity of liver cirrhosis was positively related to cost per observed day. A sensitivity analysis based on the regression equation indicated that nonsurvivorship doubles the cost per case, increased severity as measured by the Child-Pugh Index adds about 50% to the cost, and chemotherapy increases cost 2-fold. CONCLUSIONS: The relatively modest average cost per patient with HCC in Hong Kong reflects the short median survival and subsequently the limited use of inpatient care and chemotherapy.

Aged↗
PubMed2001

Quantitative correlation of cytokeratin 19 mRNA level in peripheral blood with disease stage and metastasis in breast cancer patients: potential prognostic implications.

Mortality among patients with breast cancer (BC) is mainly caused by metastasis. We determined the circulating tumor burden in BC patients by semiquantitative reverse transcription-polymerase chain reaction using carcinoembryonic antigen (CEA) and cytokeratin 19 (CK19) mRNAs as molecular markers. We distinguished the mRNA levels in circulation between BC patients and healthy controls with reference to a BC-derived cell line, SK-BR-3. We prospectively analyzed peripheral blood samples from 33 BC patients and 26 healthy controls. We found CEA mRNA in 97% of patients and 92% of normal controls, and CK19 mRNA in 72% of patients and 19% of controls. CEA and CK19 mRNAs in normal peripheral blood were most likely derived from illegitimate transcription. In 10 patients, of whom 9 (90%) developed systemic metastases, the upper limit of CK19 mRNA of normal controls was exceeded. As compared with normal controls, significantly elevated CK19 mRNA levels in the patients appeared to originate from circulating malignant BC cells (P<0.0001). It was clinically significant that the mean CK19 mRNA level increased with advancing disease stage. Of prognostic value, we report for the first time that BC patients with CK19 mRNA elevation had notably shorter (approximately 3-year reduction) overall survival than patients with normal CK19 mRNA levels (P=0.045). Quantification of CK19 mRNA may prove useful for cancer staging, disease monitoring and prognostic assessment among BC patients.

Adult↗
PubMed2000

Molecular prognostication of nasopharyngeal carcinoma by quantitative analysis of circulating Epstein-Barr virus DNA.

We investigated the prognostic implication of pretreatment plasma/serum EBV DNA concentration, as measured by real-time quantitative PCR, in nasopharyngeal carcinoma (NPC). In 91 prospectively recruited NPC patients, those with recurrence or metastasis within the first year after treatment had a higher median plasma EBV DNA concentration than those without events (41,756 copies/ml versus 5,807 copies/ml; P < 0.001, Mann-Whitney rank-sum test). In multivariate logistic regression analysis, plasma EBV DNA was an independent prognostic indicator for early clinical events [relative risk = 3.8 (95% confidence interval, 1.6-9.2 for each 10-fold increase in plasma EBV DNA concentration; P = 0.003)]. In a second cohort of 139 NPC patients followed-up for a median period of 2,027 days (interquartile range, 597-2,335 days), serum EBV DNA was found to be a significant variable associated with NPC-related death in multivariate Cox's regression analysis [relative risk = 1.6 (95% confidence interval, 1.1-2.1 for each 10-fold increase in serum EBV DNA concentration; P = 0.007)]. The quantitation of circulating EBV DNA may thus allow improved prognostication of NPC.

Adult↗
PubMed2000

Final report of a randomized trial on altered-fractionated radiotherapy in nasopharyngeal carcinoma prematurely terminated by significant increase in neurologic complications.

PURPOSE: The aim of the present study was to compare the survival, local control and complications of conventional/accelerated-hyperfractionated radiotherapy and conventional radiotherapy in nonmetastatic nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: From February 1993 to October 1995, 159 patients with newly diagnosed nonmetastatic (M0) NPC with N0 or 4 cm or less N1 disease (Ho's N-stage classification, 1978) were randomized to receive either conventional radiotherapy (Arm I, n = 82) or conventional/accelerated-hyperfractionated radiotherapy (Arm II, n = 77). Stratification was according to the T stage. The biologic effective dose (10 Grays) to the primary and the upper cervical lymphatics were 75.0 and 73.1 for Arm I and 84.4 and 77.2 for Arm II, respectively. RESULTS: With comparable distribution among the T stages between the two arms, the free from local failure rate at 5 years after radiotherapy was not significantly different between the two arms (85.3%; 95% confidence interval, 77.2-93.4% for Arm I; and 88.9%; 95% confidence interval, 81.7-96.2% for Arm II). The two arms were also comparable in overall survival, relapse-free survival, and rates of distant metastasis and regional relapse. Conventional/accelerated-hyperfractionated radiotherapy was associated with significantly increased radiation-induced damage to the central nervous system (including temporal lobe, cranial nerves, optic nerve/chiasma, and brainstem/spinal cord) in Arm II. Although insignificant, radiation-induced cranial nerve(s) palsy (typically involving VIII-XII), trismus, neck soft tissue fibrosis, and hypopituiturism and hypothyroidism occurred more often in Arm II. In addition, the complications occurred at significantly shorter intervals after radiotherapy in Arm II. CONCLUSION: Accelerated hyperfractionation when used in conjunction with a two-dimensional radiotherapy planning technique, in this case the Ho's technique, resulted in increased radiation damage to the central nervous system without significant improvement in efficacy.

Adolescent↗
PubMed2000

A phase II study of gemcitabine plus oral etoposide in the treatment of patients with advanced nonsmall cell lung carcinoma.

BACKGROUND: The authors have designed a non-cisplatin-based chemotherapy regimen for the treatment of patients with advanced nonsmall cell lung carcinoma (NSCLC). This regimen capitalizes on the mild toxicity of gemcitabine, a novel nucleoside analog. METHODS: A total of 46 chemotherapy-naive patients with histologically confirmed Stage IIIB or IV NSCLC were enrolled. Eligible patients were treated with gemcitabine 1000 mg/m(2) on Days 1, 8, and 15, plus oral etoposide 50 mg daily for 14 days, which was increased to 21 days if there was no World Health Organization (WHO) Grade 3 or 4 toxicity in the 1st 2 cycles (each cycle was 28 days long). All patients were included for analysis of response and survival according to an intention-to-treat principle. RESULTS: The overall response rate was 43.5% (95% confidence interval [CI], 30. 7-60.2%). There was 1 complete response (2.2%) and 19 partial responses (41.3%). The median survival was 48.0 weeks (95% CI, 38. 1-75.9 weeks) and the 1-year survival rate was 45% (95% CI, 29-62%). The median time to progression for all patients was 39.2 weeks (95% CI, 35.7-49.7 weeks). World Health Organization (WHO) Grade 3 and 4 anemia, neutropenia, and thrombocytopenia was reported in 29%, 32%, and 18% of patients, respectively. Two patients had reactivation of hepatitis B viral infection that resulted in WHO Grade 4 hepatic dysfunction. Other nonhematologic toxicities were uncommon. CONCLUSIONS: This non-cisplatin-based regimen of gemcitabine and oral etoposide achieved a high response and survival rate. Toxicity appeared to be less severe than that associated with existing cisplatin-based regimens. A randomized study of this regimen versus a cisplatin-based regimen is indicated.

Adult↗
PubMed2000

CTL control of EBV in nasopharyngeal carcinoma (NPC): EBV-specific CTL responses in the blood and tumors of NPC patients and the antigen-processing function of the tumor cells.

Undifferentiated nasopharyngeal carcinoma (NPC) is latently infected with EBV and expresses a restricted number of viral proteins. Studies in healthy virus carriers have demonstrated that at least some of these proteins can act as targets for HLA class I-restricted CTLs. Therefore we have explored the possibility of a CTL-based therapy for NPC by characterizing EBV-specific CTL responses in 10 newly diagnosed NPC cases and 21 healthy virus carriers from Southeast Asia. Using the autologous EBV-transformed lymphoblastoid cell line, virus-specific CTL were reactivated in vitro from PBMC, cloned, and screened for cytotoxicity against target cells expressing individual EBV proteins from recombinant vaccinia vectors. EBV-specific CTLs were identified in 6 of 10 patients and 14 of 21 controls and mainly targeted the EBV nuclear Ag 3 (EBNA3) family of viral latent proteins. However, in 3 of 10 patients and 11 of 21 controls, CTLs specific for the NPC-associated protein LMP2 were also detected, albeit at low frequency. EBV-specific CTLs were detected in tumor biopsy material obtained from 3 of 6 of the patients, indicating that functional CTL are present at the tumor site, but none was specific for tumor-associated viral proteins. To assess the Ag-presenting function in NPC we studied two NPC-derived cell lines (C15 and c666.1) and demonstrated that both were capable of processing and presenting endogenously synthesized protein to HLA class I-restricted CTL clones. Overall, our data provide a sound theoretical basis for therapeutic strategies that aim to boost or elicit LMP2-specific CTL responses in NPC patients.

Adult↗
PubMed2000

Kinetics of plasma Epstein-Barr virus DNA during radiation therapy for nasopharyngeal carcinoma.

We studied the kinetics of circulating EBV DNA in the plasma of nasopharyngeal carcinoma (NPC) patients. Serial weekly sampling of 10 NPC patients revealed a rapid decline in plasma EBV DNA concentration after treatment. In two subjects, an initial rise in the circulating EBV DNA level was observed immediately after treatment initiation. Plasma EBV DNA levels were monitored daily during the first treatment week in a second cohort of five patients, and the results indicated that an initial rise in plasma EBV DNA concentration could be observed in all subjects during the first treatment week. This observation is consistent with the liberation of EBV DNA after therapy-induced cancer cell death. After this initial rise, plasma EBV DNA concentration was found to decay with a median half-life of 3.8 days (interquartile range, 2.4-4.4 days). Kinetic analysis of circulating tumor-derived DNA during treatment may be a powerful tool for evaluating the in vivo response of NPC and other tumors to antineoplastic treatment and may improve our understanding of the biology of plasma nucleic acids.

Carcinoma, Squamous Cell↗
PubMed2000

Clinical outcomes of post-operative locoregional radiotherapy in pre-menopausal and post-menopausal Chinese women with breast cancer.

BACKGROUND AND PURPOSES: Recent randomized studies from the West show that post-operative locoregional radiotherapy improves survival in lymph node (LN) positive pre-menopausal women with breast cancer but this benefit has not been established in the Chinese population. There is no published study on clinical outcomes (locoregional recurrence, survival and toxicities) of post-operative locoregional radiotherapy in Chinese women with breast cancer. MATERIALS AND METHODS: We conducted a retrospective study of 399 female Chinese patients with breast cancer who had received post-mastectomy locoregional radiotherapy in our center between 1984 and 1990. The patients were stratified according to tumor size, menopausal and LN status. We analyzed the incidence and pattern of locoregional recurrence, distant recurrence, survival rates and toxicity related to radiotherapy. RESULTS: Of the 399 patients 216 were pre-menopausal and 183 were post-menopausal. The mean age was 49.3 years (23-83). Distribution of tumor size and LN status of the two groups was similar. Median follow-up was 71.9 months. Locoregional recurrence occurred in 57 (14.3%) patients (pre-menopausal 24 (11.1%); post-menopausal 33 (18.3%) P=0.489). Recurrence was more common in LN positive patients (18.2%) than LN negative patients (9.2%). The pattern of locoregional recurrence was: chest wall 24, axilla LN 12, supraclavicular LN 10, chest plus LN 11. The distant recurrence rate was 39.6% for all patients and 75.4% for patients with locoregional recurrences. The overall 10-year survival rate for all patients was 54%. For LN positive patients the 10-year survival rate of pre-menopausal and post-menopausal women was 38 and 51%, respectively (P=0.207), and for LN negative patients the rate was 73 and 70%, respectively (P=0.603). Acute skin toxicity included redness (30.8%), dry desquamation (12.8%), and wet desquamation (6. 8%). Long-term toxicities included skin atrophy (0.3%), telangectasia (3.3%), pneumonitis (2.8%) and brachial plexus palsy (1.3%). CONCLUSIONS: In our series Chinese patients with node-positive breast cancer have a relatively high locoregional recurrence rate in spite of mastectomy and post-operative radiotherapy. Limited use of adjuvant system chemotherapy may account, at least in part, for this finding. Clinical outcomes of post-operative radiotherapy in pre-menopausal and post-menopausal breast cancer patients are similar.

Adult↗