Biomedical subjects

David Joseph

Publications and source records attributed to David Joseph.

24 records · Page 2Linked to original sources

PubMed2004

Development of a rapid genotyping method for single nucleotide polymorphisms and its application in cancer studies.

Single nucleotide polymorphisms (SNPs) in cancer-related genes can act as low risk genetic factors for the development of this disease. SNPs have also been shown to influence the efficacy and toxicity of various cytotoxic agents used in the treatment of cancer. Progress in these important areas of cancer research relies upon rapid, inexpensive and accurate means of SNP genotyping. In the present study we describe a fluorescent PCR-based method that utilizes single strand conformation polymorphism (SSCP) analysis to distinguish between different alleles. A real-time DNA fragment analysis platform and ultra-thin, re-useable gels allow short run times and hence a relatively high throughput to be achieved. A standardised procedure for the identification of optimal running conditions for each SNP is presented. We used this fluorescent-SSCP method to genotype SNPs in the MTHFR, p21, cyclin D1, MMP-2, vitamin D receptor, TNF-alpha and IL-6 genes. Multiplex PCR of two SNPs allows up to 500 genotypes per day to be evaluated with 100% accuracy. The low start-up and running costs make this method particularly well suited for SNP genotyping studies that involve up to 1,000 DNA samples.

Base Sequence↗

PubMed2003

CpG island methylator phenotype is an independent predictor of survival benefit from 5-fluorouracil in stage III colorectal cancer.

PURPOSE: The CpG island methylator phenotype (CIMP) is observed in approximately 30% of colorectal cancer (CRC) cases and is characterized by the concurrent methylation of multiple CpG islands in tumor DNA. This phenotype (CIMP+) is more frequently observed in tumors with proximal location, microsatellite instability, and normal p53. Because it has previously been observed that each of these features is associated with a good survival benefit from 5-fluorouracil (5-FU)-based adjuvant chemotherapy, we investigated in the present study whether CIMP+ has independent predictive value. EXPERIMENTAL DESIGN: CIMP+ status was evaluated in 103 stage III CRCs from patients treated with surgery alone and for an additional 103 cases from patients treated with surgery and adjuvant 5-FU-based chemotherapy. The two cohorts were randomly pair-matched for age, sex, and tumor site, and the median length of follow-up time was 39 months. RESULTS: CIMP+ status predicted survival benefit from 5-FU treatment independently of microsatellite instability and p53 mutation status (relative risk = 0.22; 95% confidence interval, 0.06-0.84; P = 0.027). Unmeasured, high-risk confounding factors could only account for this association if they were unequally distributed between the two patient cohorts by a factor of at least 2-fold. CONCLUSIONS: CIMP+ has independent predictive significance for the survival benefit from 5-FU chemotherapy in CRC. This molecular marker should be incorporated into prospective clinical trials of fluorouracil-based therapies to confirm its clinical value.

Aged↗

PubMed2003

Outcome, morbidity, and prognostic factors in post-prostatectomy radiotherapy: an Australian multicenter study.

OBJECTIVES: To report the outcome and morbidity data for patients treated with post-prostatectomy radiotherapy (PPRT) in a multicenter collaboration. METHODS: The case records of all patients treated with PPRT from 1996 to 1998 were reviewed. Survival was calculated using Kaplan-Meier methods. Potential prognostic factors were evaluated using the Cox proportional hazards regression model. Prostate-specific antigen (PSA) remission was defined as a PSA level of 0.2 ng/mL or less. Acute and late morbidities were documented. RESULTS: We reviewed the data of 115 patients, with a median follow-up from the start of PPRT of 28.7 months. Patients were treated with adjuvant intent (n = 23), for local recurrence (n = 27), or for a detectable PSA level (n = 65). The overall and cause-specific survival rate at 5 years was 73.7% and 81.4%, respectively. The biochemical disease-free survival rate was 69.6% at 2 years and 50% at 5 years. Factors predicting for subsequent relapse on multivariate analysis were pre-PPRT PSA (P = 0.013) and post-PPRT nadir (P <0.0001). Patients with a PSA greater than 1 ng/mL fared significantly worse than those with lower levels (P <0.0001). For patients with a pretreatment PSA of less than 1 ng/mL and an operative Gleason score of 7 or less, the 5-year projected biochemical disease-free survival rate was 71%. One case of grade 3 late proctitis was recorded, and 4 patients had continued grade 3 late urinary incontinence. CONCLUSIONS: Early use of PPRT is effective and well tolerated in patients at risk of, or with proven, local recurrence.

Aged↗

PubMed2003

Acceptability of short term neo-adjuvant androgen deprivation in patients with locally advanced prostate cancer.

PURPOSE: To determine the acceptability of short term neo-adjuvant maximal androgen deprivation (MAD) to patients treated with external beam radiation for locally advanced prostate cancer. METHODS: Between 1996 and 2000, 818 patients with locally advanced, but non-metastatic, prostate cancer were entered into a randomised clinical trial (TROG 96.01), which compared radiation treatment alone with the same radiation treatment and 3 or 6 months neo-adjuvant MAD with goserelin and flutamide. Relevant symptoms, and how troublesome they were to the patient, were scored using a self-assessment questionnaire. This was completed by the patient at registration, and at specified times during and after treatment. Patients taking flutamide had liver function tests checked at regular intervals. RESULTS: All patients have completed at least 12 months follow-up after treatment. Nearly all patients completed planned treatment with goserelin, but 27% of patients in the 6-month MAD treatment arm, and 20% in the 3-month arm, had to stop flutamide early. This was mainly due to altered liver function (up to 17% patients) and bowel side effects (up to 8% patients). However, although flutamide resulted in more bowel symptoms for patients on MAD, there was significant reduction in some urinary symptoms on this treatment. Acute bowel and urinary side effects at the end of radiation treatment were similar in all treatment arms. Side effect severity was unrelated to radiation target volume size, which was reduced by MAD, but symptomatology prior to any treatment was a powerful predictor. Of the 36% of patients who were sexually active before any treatment, the majority became inactive whilst on MAD. However, sexual activity at 12 months after radiation treatment was similar in all treatment arms, indicating that the effects of short term MAD on sexual function are reversible. CONCLUSION: Despite temporary effects on sexual activity, and compliance difficulties with flutamide, short-term neo-adjuvant MAD was not perceived by patients to be a major inconvenience. If neo-adjuvant MAD in the way tested can be demonstrated to lead to improved biochemical control and/or survival, then patients would view these therapeutic gains as worthwhile. Compliance with short-term goserelin was excellent, confirming that LH-RH analogues have a potential role in more long-term adjuvant treatment. However, for more protracted androgen deprivation, survival advantages and deleterious effects need to be assessed in parallel, in order to determine the optimal duration of treatment.

Adult↗

PubMed2003

Prognostic significance of microsatellite instability and Ki-ras mutation type in stage II colorectal cancer.

OBJECTIVES: The survival of stage II colorectal cancer (CRC) patients is approximately 70% at 5 years. Identification of the patient subgroup at high risk for tumour recurrence and death would allow more informed use of chemotherapy for this stage of disease. Several clinical and pathological factors have been reported to associate with worse survival. In the present study we investigated the prognostic significance of two major genetic alterations in CRC: microsatellite instability (MSI+) and the type of Ki-RAS mutation. METHODS: PCR-based molecular techniques were used to screen for MSI+ and Ki-RAS mutation in 396 stage II CRC patients with an average follow-up time of 75 months. Clinicopathological information was obtained by retrospective review of pathology reports. RESULTS: Prominent vascular invasion was identified in 19% of cases and was found to be an independent prognostic factor for poor outcome (relative risk = 2.08, 95% confidence interval: 1.22-3.57, p = 0.008). The MSI+ phenotype was found in 23% of proximal tumours and Ki-RAS mutations in 38% of the overall series. Neither MSI+ nor the type of Ki-RAS mutation showed prognostic significance in this cohort of stage II CRC. CONCLUSIONS: MSI+ and Ki-RAS mutation type are not useful markers for the identification of high-risk stage II CRC patients. Further prospective and/or cohort studies are required to determine whether these molecular changes have predictive value for survival benefit from 5-fluorouracil-based adjuvant chemotherapy.

Adult↗

PubMedDate not supplied

Lack of association between CCND1 G870A polymorphism and the risk of breast and colorectal cancers.

BACKGROUND: The aim of this case-control study was to investigate whether the common G870A polymorphism in the Cyclin D1 gene (CCND1) is a risk factor for breast and colorectal cancers in an Australian population. PATIENTS AND METHODS: A total of 339 breast and 569 colorectal cancer cases were studied, together with 327 age-matched controls. Genotyping for the G870A polymorphism in CCND1 was carried out using single strand conformation polymorphism and Pyrosequencing methods. RESULTS: Comparison of the CCND1 G870A genotype frequencies revealed no significant associations between presence of the A allele and the risk of either breast or colorectal cancer. No associations were noted between presence of the A allele and pathological features of these tumours or patient survival. CONCLUSION: Although the CCND1 G870A polymorphism has been reported as a genetic risk factor for some tumour types, it does not appear to be linked to the risk of breast and colorectal cancers.

Alleles↗