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Bhuvanesh Singh

Publications and source records attributed to Bhuvanesh Singh.

At least 55 records · Page 3Linked to original sources
PubMed2004

Head and neck soft tissue sarcomas: a multivariate analysis of outcomes.

BACKGROUND: Soft tissue sarcomas of the head and neck region represent a rare group of tumors of which a limited number of published individual- and institution-based experiences exist. METHODS: We performed an analysis of head and neck sarcoma patients identified from our institution between 1973 and 1999. Exclusion criteria included pediatric rhabdomyosarcomas, sarcomas of the neuromeningeal axis or non-head and neck primary disease sites, and bone sarcomas. All cases underwent pathologic re-review before statistical analysis. RESULTS: After pathologic review, 111 head and neck sarcoma patients remained (mean age, 47 +/- 20 years). The median duration of follow-up was 51 months; the actuarial 5-year relapse-free, disease-specific, and overall survivals were 55%, 52%, and 44%, respectively. Forty-six percent remained free of recurrence at the most recent follow-up, and the most common site of recurrence was local followed by distant sites. By multivariate analysis, size and grade significantly influenced relapse-free, disease-specific, and overall survivals, whereas margin status additionally influenced relapse-free survival. Subset analysis of the fibrosarcoma/malignant fibrous histiocytoma and desmoid/dermatofibrosarcoma protuberans histologies was undertaken. CONCLUSIONS: Size >5 cm and high-grade histology are considered poor prognostic indicators. Patients with either of these characteristics should be considered for adjuvant trials.

Adult↗
PubMed2004

Squamous cell carcinoma related oncogene regulates angiogenesis through vascular endothelial growth factor-A.

BACKGROUND: Squamous cell carcinoma related oncogene expression (SCCRO) correlates with vascular endothelial growth factor-A expression. This data is validated in human lung tumors and provides a putative pathway for angiogenesis in a subset of squamous cell carcinomas. Squamous cell carcinoma related oncogene is a novel oncogene identified by positional cloning of a recurrent amplification at 3q26.3. It is over-expressed in 39.8% of lung, head and neck, cervical, and ovarian carcinomas. SCCRO imparts an aggressive phenotype to affected cancers, which may be related to increased angiogenesis due to SCCRO expression. Our previous work has demonstrated a link between SCCRO and vascular endothelial growth factor-A (VEGF-A) expression in vitro, suggesting a mechanism for SCCRO-induced angiogenesis. The present study aims to confirm and validate this link between SCCRO and VEGF-A expression in an ex vivo human tumor cohort. METHODS: Fresh tissue was collected at Memorial Sloan-Kettering Cancer Center from 34 patients undergoing primary resection of lung squamous cell carcinomas. RNA was extracted from this tissue, reverse-transcribed, and real-time polymerase chain reaction (RT-PCR) was carried out using a BioRad iQ iCycler with SYBR green fluorophore. Microvessel counting was performed on the tumor specimens using CD34 immunohistochemistry. RESULTS: The expression of both SCCRO and VEGF-A mRNA varies widely in both tumor and normal tissue. SCCRO and VEGF-A co-expression was significantly correlated (R(2) = 0.63; P < 0.032). Microvessel counts were not associated with expression of SCCRO or VEGF-A and failed to significantly predict survival. VEGF-A expression in this patient group is a predictor of overall survival (P < 0.032). CONCLUSIONS: VEGF-A expression correlates with SCCRO expression in these primary human lung squamous cell carcinomas and is a predictor of clinical behavior. This data supports the association of SCRRO and VEGF-A in the induction of angiogenesis.

Aged↗
PubMed2003

Human papillomavirus DNA and p53 polymorphisms in squamous cell carcinomas from Fanconi anemia patients.

Fanconi anemia is an autosomal recessive disorder characterized by congenital malformations, bone marrow failure, and the development of squamous cell carcinomas (SCCs) and other cancers. Recent clinicopathologic evidence has raised the possibility that an environmental factor such as human papillomavirus (HPV) may be involved in the pathogenesis of SCCs in Fanconi anemia patients. Given the high prevalence of p53 mutations in SCCs among the general population and the lack of p53 mutations in HPV-related carcinogenesis, we evaluated the role of HPV and p53 mutations and polymorphisms in SCC from Fanconi anemia patients. We used polymerase chain reaction (PCR) screening and real-time PCR to detect and quantify HPV DNA in DNA extracted from microdissected SCCs obtained from 24 Fanconi anemia patients (n = 25 SCCs; case subjects) and 50 age-, sex-, and tumor site-matched SCC patients without Fanconi anemia (n = 50 SCCs; control subjects). We PCR-amplified and sequenced exons 4-9 of the p53 gene from SCC DNA. We detected HPV DNA in 84% of the SCC specimens from the case subjects and in 36% of the SCC specimens from the control subjects (P<.001). The prevalence of p53 mutations in SCCs from the case subjects (0%, 0/25) was statistically significantly lower than that of SCCs from the control subjects (36%, 12/33; P<.001). A greater proportion of patients with Fanconi anemia and SCC were homozygous for Arg72, a p53 polymorphism that may be associated with increased risk for HPV-associated human malignancies, than an ethnically-matched cohort of Fanconi anemia patients without SCC (75% versus 51%; P =.05). These data suggest that Fanconi anemia is associated with increased susceptibility to HPV-induced carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed2003

Spindle assembly checkpoint defects and chromosomal instability in head and neck squamous cell carcinoma.

Alterations in chromosomal number and structure are found in most solid malignancies including head and neck squamous cell carcinoma (HNSC), however, the presence of ongoing, chromosomal instability in HNSC and its relation to spindle assembly checkpoint defects has not been formally demonstrated. We investigated the status of chromosomal instability (CIN) in HNSC primary tumors and cell lines as well as spindle assembly checkpoint integrity in HNSC cell lines. Centromeric fluorescence in situ hybridization (FISH) was carried out on expanded single cell-derived colonies from HNSC cell lines and primary HNSC touch preparations. The deviation of chromosomes from the modal number in single cell derived colonies was 18.4-27% in 6 HNSC cell lines, and 2-3% in a control cell line, HCT116. Twelve primary tumors and 4 normal controls were also studied; all primary tumors demonstrated significant deviation from the modal chromosomal number (average 33.7%, range = 29.9-43.9%), compared to normal controls (average 4.6%, range = 3.6-5.6%). Additional characterization of the rate of chromosomal breakage was carried out by dual color FISH simultaneously using centromeric and telomeric probes for individual chromosomes on expanded singe cell-derived colonies and primary HNSC. Control HCT 116 colonies demonstrated a mean discordance between number of centromeric and telomeric hybridization signals in 21% (range = 19-23%) of cells, whereas HNSC cell line colonies demonstrated a mean discordance of 50% (range = 38-55%), with the majority of instances of discordant signal indicating telomeric loss. Similarly, touch preparations from primary HNSC demonstrated discordance in hybridization signal of centromeric vs. telomeric signal of 26.3% (range = 18.5-42%), with normal controls showing a rate of discordance of 6.4% (range = 4-8%). Finally, all 6 HNSC cell lines demonstrated partial impairment of mitotic arrest in response to nocodazole, indicating that impairment of the spindle assembly checkpoint may contribute to chromosomal instability in HNSC. Ongoing instability in chromosomal number and structure are consistent features of primary HNSC and cell lines. Spindle assembly checkpoint impairment occurs in HNSC cell lines and may contribute to chromosomal instability in HNSC.

Carcinoma, Squamous Cell↗
PubMed2003

Craniofacial surgery for malignant skull base tumors: report of an international collaborative study.

BACKGROUND: Malignant tumors of the skull base are rare. Therefore, no single center treats enough patients to accumulate significant numbers for meaningful analysis of outcomes after craniofacial surgery (CFS). The current report was based on a large cohort that was analyzed retrospectively by an International Collaborative Study Group. METHODS: One thousand three hundred seven patients who underwent CFS in 17 institutions were analyzable for outcome. The median age was 54 years (range, 1-98 years). Definitive treatment prior to CFS had been administered in 59% of patients and included radiotherapy in 367 patients (28%), chemotherapy in 151 patients (12%), and surgery in 523 patients (40%). The majority of tumors (87%) involved the anterior cranial fossa. Squamous cell carcinoma (29%) and adenocarcinoma (16%) were the most common histologic types. The margins of surgical resection were reported close/positive in 412 patients (32%). Adjuvant postoperative radiotherapy was received by 510 patients (39%), and chemotherapy was received by 57 patients (4%). RESULTS: Postoperative complications were reported in 433 patients (33%), with local wound complications the most common (18%). The postoperative mortality rate was 4%. With a median follow-up of 25 months, the 5-year overall, disease-specific, and recurrence-free survival rates were 54%, 60%, and 53%, respectively. The histology of the primary tumor, its intracranial extent, and the status of surgical margins were independent predictors of overall, disease-specific, and recurrence-free survival on multivariate analysis. CONCLUSIONS: CFS is a safe and effective treatment option for patients with malignant tumors of the skull base. The histology of the primary tumor, its intracranial extent, and the status of surgical margins are independent determinants of outcome.

Adolescent↗
PubMed2003

High incidence of head and neck squamous cell carcinoma in patients with Fanconi anemia.

BACKGROUND: Fanconi anemia (FA) is a rare autosomal recessive disorder characterized by a high degree of genomic instability and predisposition to cancer development. Recent evidence suggests that the incidence of head and neck squamous cell carcinoma (HNSCC) may be increased in patients with FA. OBJECTIVE: To determine the cumulative incidence, tumor distribution, and outcome of HNSCC in patients with FA. DESIGN AND SETTING: We analyzed data from 754 subjects from the International Fanconi Anemia Registry, a prospectively collected database of patients with FA. MAIN OUTCOME MEASURES: Cumulative incidence of HNSCC and 2-year overall, relapse-free and disease-specific survival. RESULTS: Of the 754 patients in the International Fanconi Anemia Registry, 19 (3%) had HNSCC. This is a significantly higher incidence of HNSCC compared with that observed in the general population (standardized incidence ratio, 500; 95% confidence interval, 300-781) (P<.001). The patients' age ranged from 15 to 49 years (median, 31 years), and there was a 2:1 female predominance. Surgical treatment was well tolerated (n = 17); however, radiation therapy and chemotherapy were associated with significant morbidity and mortality. Of the 19 patients, 10 (53%) developed locoregional recurrences within a median of 16 months from diagnosis. The median follow-up was 29 months. The 2-year disease-specific, overall, and relapse-free survival rates were 49%, 49%, and 42%, respectively. The cumulative incidence of relapse by the age of 40 years was 50%. CONCLUSIONS: In patients with FA, there is a high incidence of aggressive HNSCC at a young age. Surgery remains the mainstay of treatment because patients with FA tolerate radiation therapy and chemotherapy poorly, with significant morbidity. An increased understanding of FA-associated malignancies is not only important in the clinical management of patients with FA but can also elucidate the role of chromosomal instability in the development of HNSCC in general.

Adolescent↗
PubMed2003

Comprehensive molecular cytogenetic characterization of cervical cancer cell lines.

We applied a combination of molecular cytogenetic methods, including comparative genomic hybridization (CGH), spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH), to characterize the genetic aberrations in eight widely used cervical cancer (CC) cell lines. CGH identified the most frequent chromosomal losses including 2q, 3p, 4q, 6q, 8p, 9p, 10p, 13q, and 18q; gains including 3q, 5p, 5q, 8q, 9q, 11q, 14q, 16q, 17q, and 20q; and high-level chromosomal amplification at 3q21, 7p11, 8q23-q24, 10q21, 11q13, 16q23-q24, 20q11.2, and 20q13. Several recurrent structural chromosomal rearrangements, including der(5)t(5;8)(p13;q23) and i(5)(p10); deletions affecting chromosome bands 5p11, 5q11, and 11q23; and breakpoint clusters at 2q31, 3p10, 3q25, 5p13, 5q11, 7q11.2, 7q22, 8p11.2, 8q11.2, 10p11.2, 11p11.2, 14q10, 15q10, 18q21, and 22q11.2 were identified by SKY. We detected integration of HPV16 sequences by FISH on the derivative chromosomes involving bands 18p10 and 18p11 in cell line C-4I, 2p16, 5q21, 5q23, 6q, 8q24, 10, 11p11, 15q, and 18p11 in Ca Ski, and normal chromosome 17 at 17p13 in ME-180. FISH analysis was also used further to determine the copy number changes of PIKA3CA and MYC. This comprehensive cytogenetic characterization of eight CC cell lines enhances their utility in experimental studies aimed at gene discovery and functional analysis.

Chromosome Aberrations↗
PubMed2003

Parathyroid neoplasms: clinical, histopathological, and tissue microarray-based molecular analysis.

We studied 45 patients with typical and 8 with atypical parathyroid adenomas as well as 20 with parathyroid carcinomas. Clinical, pathological, and molecular analyses were conducted on all adenomas. Clinical data were analyzed for 20, histopathologic slides for 16, and tissue specimens for 8 patients with carcinoma. Molecular expression profiles were investigated by immunohistochemistry (IHC) for Ki-67, p53, mdm2, p21, Bcl-2, cyclin D1, and p27 on paraffin-embedded tissues arrayed on tissue microarrays. Trabecular growth and vascular, capsular, and soft-tissue invasion were characteristic of parathyroid carcinomas but not of typical adenomas. No adenomas recurred. Seventy-four percent of carcinomas recurred, most in the neck. Seventy-nine percent of patients with such illness died of disease after an indolent, multiply recurrent course responsive to repeated resections; the 5-year survival rate was 50%. High Ki-67 proliferative index was seen in 2% of adenomas and 25% of carcinomas, whereas p27 expression was present in 80% of adenomas and 18% of carcinomas. The molecular phenotype, p27(+)Bcl-2(+)Ki-67(-)mdm2(+), was observed in 76%, 29%, and 0% of typical and atypical adenomas and carcinomas, respectively. The complexity of molecular phenotypes increased with tumor aggressiveness. Parathyroid carcinoma is an aggressive disease with a propensity for multiple recurrences. It is characterized by capsular, vascular, and soft-tissue invasion. Recurrence portends poor outcome. Molecular markers, Ki-67 and p27, may distinguish parathyroid carcinoma from adenoma. The molecular phenotype, p27(+)Bcl-2(+)Ki-67(-)mdm2(+), appears to be unique to nonmalignant parathyroid tumors, and multimarker phenotypes are more complex in carcinomas.

Adenoma↗
PubMed2003

Clinical nodal stage is an independently significant predictor of distant failure in patients with squamous cell carcinoma of the larynx.

OBJECTIVE: To determine the impact of clinical nodal stage on distant metastasis (DM) in patients with squamous cell carcinoma of the larynx (SCCL). METHODS: Six hundred sixty-two previously untreated SCCL patients treated at a tertiary care cancer center from January 1984 to December 1998 were eligible for analysis. The end point of interest was development of DM following treatment. Distant metastasis-free survival (DMFS) was calculated by the Kaplan-Meier method; predictors of outcome were identified by univariate and multivariate analysis. The primary tumor site was glottic in 55%, supraglottic in 40%, and trans/sub glottic in 5%; 40% had locoregionally advanced (stage III/IV) tumors. At initial presentation, 25% of patients (12% N1, 11% N2, and 2% N3) had clinically metastatic nodes. RESULTS: DM were recorded in 67 patients (10%; lung, 45%; soft tissue, 13%; bone, 10%; multiple sites, 28%). The median time to DM was 18 months (range, 1-109). With a median follow-up of 60 months, the 5-year DMFS was 88%. Even after accounting for the type of index treatment, the only significant predictor of worse DMFS on multivariate analysis was a higher clinical N stage (P < 0.0001). The relative risk for DM was 0.5 (95% CI, 0.2-1.4; P = NS) for cN1, 3.2 (95% CI, 1.7-5.9; P < 0.0001) for cN2, and 7.5 (95% CI, 3.1-17.9; P < 0.0001) for cN3 disease compared with clinically N0 patients. CONCLUSION: Regardless of the index treatment modality, primary tumor site, or T stage, a higher clinical N stage at the time of presentation independently and significantly increases the risk of DM in patients with SCCL.

Carcinoma, Squamous Cell↗
PubMed2003

The role of novel oncogenes squamous cell carcinoma-related oncogene and phosphatidylinositol 3-kinase p110alpha in squamous cell carcinoma of the oral tongue.

PURPOSE: Amplification at chromosome 3q26.3 is a common and crucial event in head and neck squamous cell carcinoma (HNSCC), impacting significantly on tumor progression and clinical outcome. Two novel oncogenes, namely squamous cell carcinoma (SCC)-related oncogene (SCCRO) and PIK3CA (gene encoding phosphatidylinositol-3 kinase catalytic alpha-polypeptide), have been identified as targets of 3q26.3 amplification. This study aimed to delineate the role of SCCRO and PIK3CA in the pathogenesis of oral tongue SCC. EXPERIMENTAL DESIGN: The association between gene copy number for SCCRO and PIK3CA measured by fluorescence in situ hybridization and level of mRNA expression quantitated by real-time reverse transcription-PCR was assessed in a panel of human HNSCC cell lines. In addition, gene expression in 49 consecutive primary SCCs of the oral tongue was determined and correlated with clinicopathological characteristics and outcome. RESULTS: The mRNA level of SCCRO and PIK3CA was significantly correlated to the gene copy number in nine HNSCC cell lines. In addition, the expression level of SCCRO and PIK3CA was significantly greater in malignant tissues compared with those in histologically normal mucosae (2.17- and 2.46-fold, respectively; P < 0.001). Matched tumor normal control analysis revealed that 24.5 and 69.4% of patients expressed high levels of SCCRO and PIK3CA, respectively. Univariate analyses demonstrated that SCCRO overexpression correlated with nodal metastases (P = 0.05) and advanced stage (P = 0.02), whereas PIK3CA overexpression was associated with vascular invasion (P = 0.04). Only SCCRO overexpression was associated with disease-specific (P = 0.04) and overall survival (P = 0.02). Furthermore, SCCRO overexpression remained an independent predictor for cervical nodal metastasis on multivariate regression analysis (chi(2) likelihood ratio = 4.38; P = 0.04). CONCLUSIONS: Although both SCCRO and PIK3CA may play a role in the pathogenesis of oral tongue SCC through amplification at 3q26, SCCRO appears to be a significant predictor of regional metastasis and may be a marker for tumor aggressiveness and clinical outcome.

Adult↗
PubMed2002

Chromosomal aberrations in patients with head and neck squamous cell carcinoma do not vary based on severity of tobacco/alcohol exposure.

BACKGROUND: Head and neck squamous cell carcinomas (HNSCC) have been causally associated with tobacco and alcohol exposure. However, 10-15% of HNSCC develop in absence of significant carcinogen exposure. Several lines of evidence suggest that the genetic composition of HNSCC varies based on the extent of tobacco/alcohol exposure, however, no genome wide measures have been applied to address this issue. We used comparative genomic hybridization (CGH) to screen for the genetic aberrations in 71 patients with head and neck squamous cell carcinoma and stratified the findings by the status of tobacco/alcohol exposure. RESULTS: Although the median number of abnormalities (9), gains (6) and losses (2) per case and the overall pattern of abnormalities did not vary significantly by the extent of tobacco/alcohol exposure, individual abnormalities segregating these patients were identified. Gain of 1p (p = 0.03) and 3q amplification (p = 0.05) was significantly more common in patients with a history of tobacco/alcohol exposure. CONCLUSIONS: This data suggests that the overall accumulated chromosomal aberrations in head and neck squamous cell carcinoma are not significantly influenced by the severity of tobacco/alcohol exposure with limited exceptions.

Adult↗
PubMed2002

Improved outcomes in patients with osteogenic sarcoma of the head and neck.

BACKGROUND: The current study reviews the authors' recent institutional experience in the treatment of osteosarcoma of the head and neck (OSHN). METHODS: The clinical records of 44 patients who were treated between 1981 and 1998 for OSHN were reviewed retrospectively. Archived histologic material was reviewed and data were analyzed to identify factors predictive of disease control and survival. Outcomes were compared with a previously reported historic cohort treated at the study institution. RESULTS: Patients ranged in age from 6 to 64 years (median, 31 years). The mandible was the primary site in 18 patients (41%), the maxilla in 20 patients (45%), and the skull in 6 patients (14%). Surgery was employed in all 44 patients, neoadjuvant chemotherapy was administered in 30 patients (68%), and postoperative radiation therapy was given to 7 patients (16%). The surgical excision margins were positive in 13 patients (30%). High-grade lesions were reported in 50% patients and low-grade lesions were noted in 18% of patients (grade was not assessable in 32%). Histologic response was "unfavorable" in 22 of 30 patients (73%) who were treated with neoadjuvant chemotherapy. The 3-year overall, disease-specific, and recurrence-free survival rates were approximately 81%, 81%, and 73%, respectively (median follow-up of 41 months). Positive surgical margins were found to be the only significant predictor of worse disease-specific survival. Compared with the historical cohort, the current experience demonstrated an obvious improvement in the 5-year local control (35% vs. 78%), distant metastases (37% vs. 13%), and overall survival (23% vs. 70%). CONCLUSIONS: Negative surgical margins were found to be the only significant predictor of overall and disease-specific survival. The results of the current study represent a considerable improvement over the authors' previously published experience and compare favorably with the results reported in the literature.

Adolescent↗
PubMed2002

A 20-year perspective on the International Fanconi Anemia Registry (IFAR).

Fanconi anemia (FA) is an autosomal recessive disorder characterized by cellular hypersensitivity to DNA cross-linking agents and cancer predisposition. Recent evidence for the interactions of ataxia-telangiectasia mutated protein ATM and breast cancer susceptibility proteins BRCA1 and BRCA2 (identified as FANCD1) with other known FA proteins suggests that FA proteins have a significant role in DNA repair/recombination and cell cycle control. The International Fanconi Anemia Registry (IFAR), a prospectively collected database of FA patients, allows us the unique opportunity to analyze the natural history of this rare, clinically heterogeneous disorder in a large number of patients. Of the 754 subjects in this study, 601 (80%) experienced the onset of bone marrow failure (BMF), and 173 (23%) had a total of 199 neoplasms. Of these neoplasms, 120 (60%) were hematologic and 79 (40%) were nonhematologic. The risk of developing BMF and hematologic and nonhematologic neoplasms increased with advancing age with a 90%, 33%, and 28% cumulative incidence, respectively, by 40 years of age. Univariate analysis revealed a significantly earlier onset of BMF and poorer survival for complementation group C compared with groups A and G; however, there was no significant difference in the time to hematologic or nonhematologic neoplasm development between these groups. Multivariate analysis of overall survival time shows that FANCC mutations (P =.007) and hematopoietic stem cell transplantation (P = <.0001) define a poor-risk subgroup. The results of this study of patients registered in the IFAR over a 20-year period provide information that will enable better prediction of outcome and aid clinicians with decisions regarding major therapeutic modalities.

Bone Marrow Diseases↗
PubMed2002

Alteration of p53 pathway in squamous cell carcinoma of the head and neck: impact on treatment outcome in patients treated with larynx preservation intent.

PURPOSE: To identify the role of p53 pathway alteration(s) as predictors of treatment outcome in patients with advanced, resectable, squamous cell carcinoma (SCC) of the larynx and pharynx treated with larynx preservation (LP) intent. PATIENTS AND METHODS: Seventy-one patients treated on two consecutive LP protocols were studied based on availability of representative tissues. We analyzed the expression pattern of p53, its upstream regulator mdm2, and downstream transcriptional target p21/WAF1 by immunohistochemistry. Positive phenotype was defined as >or= 20% of tumor cells showing nuclear immunoreactivity. Results were correlated with treatment outcomes. RESULTS: Positive phenotype was observed in 35 (49%) of 71 cases for p53, in 52 (74%) of 70 for mdm2, and in 37 (54%) of 68 for p21. There was no correlation between p53 phenotype and p21 nuclear accumulation. The mdm2-negative phenotype was most predictive of major response at the primary tumor site (P =.088). p53-positive phenotype was associated with worse local control with LP (LCLP; 49% v 23%, P =.053) and inferior overall survival (OS; 51% v 29%, P =.017) at 5 years. On Cox regression analysis, p53-positive phenotype predicted inferior OS (P =.033) and showed a trend for worse LCLP (P =.102). When analyzed in a multivariate model as continuous variables, p53 showed a stronger correlation with inferior OS (P <.01), and mdm2 was associated with worse OS (P <.01). CONCLUSION: Among the three markers studied, our data support p53 phenotype as the most informative predictor of unfavorable outcomes in the LP setting, and suggest a role for mdm2 phenotype that requires further exploration. Our analysis does not support a p53-dependent mechanism for p21 expression. Prospective and larger studies are necessary before integration of these molecular markers as part of molecular staging and predictors for organ preservation or other outcomes.

Adult↗
PubMed2002

p53 regulates cell survival by inhibiting PIK3CA in squamous cell carcinomas.

Interactions between the p53 and PI3K/AKT pathways play a significant role in the determination of cell death/survival. In benign cells these pathways are interrelated through the transcriptional regulation of PTEN by p53, which is required for p53-mediated apoptosis. PTEN exerts its effects by decreasing the phosphorylated AKT fraction, thereby diminishing prosurvival activities. However, the link between these pathways in cancer is not known. In this study, PIK3CA, encoding the p110alpha catalytic subunit of PI3K, is identified as an oncogene involved in upper aerodigestive tract (UADT) carcinomas. Simultaneous abnormalities in both pathways are rare in primary tumors, suggesting that amplification of PIK3CA and mutation of p53 are mutually exclusive events and either event is able to promote a malignant phenotype. Moreover, the negative effect of p53 induction on cell survival involves the transcriptional inhibition of PIK3CA that is independent of PTEN activity, as PTEN is not expressed in the primary tumors. Conversely, constitutive activation of PIK3CA results in resistance to p53-related apoptosis in PTEN deficient cells. Thus, p53 regulates cell survival by inhibiting the PI3K/AKT prosurvival signal independent of PTEN in epithelial tumors. This inhibition is required for p53-mediated apoptosis in malignant cells.

Apoptosis↗
PubMed2002

Molecular classification of head and neck squamous cell carcinoma using cDNA microarrays.

Squamous cell carcinomas of the head and neck constitute an anatomically heterogeneous group of neoplasms that share in common a causal association with tobacco and alcohol exposure. The clinical course of these neoplasms is difficult to predict based on established prognostic clinicopathological criteria. Given the genetic complexity of head and neck cancers, it is not surprising that correlations with individual genetic abnormalities have also been disappointing. Several authors have suggested that global gene expression patterns can be used to subgroup patients with cancer. Here we report the use of cDNA microarrays containing 9216 clones to measure global patterns of gene expression in these neoplasms. We have used a statistical algorithm to identify 375 genes, which divide patients with head and neck tumors into two clinically distinct subgroups based on gene expression patterns. Our results demonstrate that gene expression profiling can be used as a predictor of outcome.

Adult↗
PubMed2002

Sentinel lymph node biopsy for cutaneous head and neck melanomas.

OBJECTIVE: To report the results of sentinel lymph node biopsy (SLNB) for cutaneous head and neck melanomas (CMHNs). DESIGN: Consecutive series followed for a median of 20 months. SETTING: Tertiary cancer care center. PATIENTS: Fifty-six individuals with clinically node-negative CMHN, median Breslow thickness, 2.6 mm (range, 0.2-20.0 mm). INTERVENTIONS: Preoperative technetium 99m sulfur colloid lymphoscintigraphy (PLSG) followed within 4 hours by intraoperative handheld gamma probe localization (IHGP). Intraoperative injection of 1% isosulfan blue dye (IBD) was used in 48 patients. Immediate completion nodal dissection was performed for metastatic SLNs on intraoperative frozen section analysis and monitoring for negative SLNs. MAIN OUTCOME MEASURES: Rate of SLN identification, SLN and non-SLN positivity, same-basin recurrence, and disease-specific and recurrence-free survival. RESULTS: Combination of IHGP and IBD improved SLN identification to 96% from 93% for IHGP and 73% for IBD alone. Four patients had a positive SLN on frozen section analysis. A negative SLNB correctly predicted regional nodal control in 47 of 48 patients but missed 1 of 5 patients who had regional lymphatic disease. All 4 patients who failed SLNB remain alive and free of recurrent disease. Two-year Kaplan-Meier disease-specific and relapse-free survival was 91% and 88%, respectively. Two-year disease-specific survival was 93% for SLN-negative patients and 50% for SLN-positive patients (P=.20). CONCLUSIONS: Combining PLSG with IHGP and IBD improves the success rate of SLNB. Although SLNB is a reliable indicator of the status of the draining lymphatic basins in CMHN, patients with negative SLNs must be observed for longer periods to understand the true implications of the procedure.

Adolescent↗