Biomedical subjects

Inderpal S Sarkaria

Publications and source records attributed to Inderpal S Sarkaria.

6 recordsLinked to original sources

PubMed2006

Use of cigarette-smoking history to estimate the likelihood of mutations in epidermal growth factor receptor gene exons 19 and 21 in lung adenocarcinomas.

PURPOSE: Lung adenocarcinomas with mutations in exons 19 and 21 of the epidermal growth factor receptor gene (EGFR) demonstrate sensitivity to gefitinib or erlotinib. Investigators have reported an association between EGFR mutations and the amount and duration of cigarette smoking, with the highest incidence of mutations seen in never smokers. METHODS: EGFR exon 19 and 21 mutation status was determined in 265 tumor samples using direct sequencing, polymerase chain reaction (PCR), or PCR-based restriction fragment length polymorphism analysis. A detailed smoking history was obtained. Patients were categorized as never smokers (< 100 lifetime cigarettes), former smokers (quit > or = 1 year ago), or current smokers (quit < 1 year ago). RESULTS: We detected EGFR mutations in 34 (51%) of 67 never smokers (95% CI, 38% to 64%), 29 (19%) of 151 former smokers (95% CI, 13% to 27%), and two (4%) of 47 current smokers (95% CI, 1% to 16%). Significantly fewer EGFR mutations were found in people who smoked for more than 15 pack-years (P < .001) or stopped smoking less than 25 years ago (P < .02) compared with individuals who never smoked. The number of smoking pack-years and smoke-free years predicted the prevalence of EGFR mutations (areas under receiver operating characteristic curve = 0.78 and 0.77, respectively). CONCLUSION: The likelihood of EGFR mutations in exons 19 and 21 decreases as the number of pack-years increases. Mutations were less common in people who smoked for more than 15 pack-years or who stopped smoking cigarettes less than 25 years ago. These data can assist clinicians in assessing the likelihood of exon 19 and 21 EGFR mutations in patients with lung adenocarcinoma when mutational analysis is not feasible.

Adenocarcinoma↗

PubMed2005

Gene expression profiling allows distinction between primary and metastatic squamous cell carcinomas in the lung.

Lung neoplasms commonly develop in patients previously treated for head and neck carcinomas. The derivation of these tumors, either as new primary lung cancers or as metastatic head and neck cancers, is difficult to establish based on clinical or histopathologic criteria since both are squamous cell carcinomas and have identical features under light microscopy. However, this distinction has significant treatment and prognostic implications. Gene expression profiling was performed on a panel of 52 sequentially collected patients with either primary lung (n = 21) or primary head and neck (n = 31) carcinomas using the Affymetrix HG_U95Av2 high-density oligonucleotide microarray. Unsupervised hierarchical clustering with Ward linkage and the Pearson correlation metric was performed. To assess robustness, bootstrap resampling was performed with 1,000 iterations. A t test of the normalized values for each gene was used to determine the genes responsible for segregating head and neck from lung primary carcinomas, and those with the most differential expression were used for later analyses. In the absence of a large "test" set of tumors, we used a supervised leave-one-out cross-validation to test how well we could predict the tumor origin. Once a gene expression profile was established, 12 lung lesions taken from patients with previously treated head and neck cancers were similarly analyzed by gene expression profiling to determine their sites of origin. Unsupervised clustering analysis separated the study cohort into two distinct groups which reliably remained segregated with bootstrap resampling. Group 1 consisted of 30 tongue carcinomas. Group 2 consisted of 21 lung cancers and 1 tongue carcinoma. The clustering was not changed even when normal lung or tongue profiles were subtracted from the corresponding carcinomatous lesions, and a leave-one-out cross-validation showed a 98% correct prediction (see Supplementary Data 1). A minimum set of 500 genes required to distinguish these groups was established. Given the ability to segregate these lesions using molecular profiling, we analyzed the lung tumors of undetermined origin. All cases clearly clustered with either lung or tongue tumor subsets, strongly supporting our hypothesis that this technique could elucidate the tissue of origin of metastatic lesions. Although histologically similar, squamous cell carcinomas have distinct gene expression profiles based on their anatomic sites of origin. Accordingly, the application of gene expression profiling may be useful in identifying the derivation of lung nodules and consequently enhances treatment planning.

Algorithms↗

PubMed2004

SCCRO expression correlates with invasive progression in bronchioloalveolar carcinoma.

BACKGROUND: Overexpression of squamous cell carcinoma-related oncogene (SCCRO) is associated with invasive progression and poor outcomes in non-small cell lung cancer. We assessed the role of SCCRO as a tumor marker in bronchioloalveolar carcinoma (BAC), a subtype of adenocarcinoma exhibiting evidence of histologic tumor progression. We hypothesized that SCCRO expression would correlate with invasive tumor phenotypes and worse survival in BAC. METHODS: We classified 150 tumors as pure BAC, BAC with focal invasion, or adenocarcinoma with BAC features. A tissue microarray was constructed from areas of benign lung, BAC, and invasive adenocarcinoma in these tumors. Squamous cell carcinoma-related oncogene expression was graded by immunohistochemistry from 0 to 3 (absent, low, moderate, or high), with positive SCCRO phenotype defined as grade 3. Squamous cell carcinoma-related oncogene specificity was determined by Wilcoxon rank test and area under the receiver-operator curve, survival by the Kaplan-Meier method, and correlation with prognostic factors by log-rank test. RESULTS: Of the 86.0% (129 of 150) of specimens suitable for analysis, positive SCCRO phenotype was seen in 16.3% (21 of 129) and was 100.0% specific for tumor versus benign tissue (area under receiver-operator curve, 0.92). Positive SCCRO phenotype was greater in tumors with increasing degrees of invasive histologic type (7.0% pure BAC, 13.6% BAC with focal invasion, and 28.6% adenocarcinoma with BAC features; p = 0.02). Low-level SCCRO expression was present in 83.9% (99 of 118) of benign tissues and correlated with tobacco use and poor survival (p = 0.05). CONCLUSIONS: Squamous cell carcinoma-related oncogene is a marker of invasive tumor progression in BAC. Low-level expression in adjacent benign lung predicts worse survival, and may represent field cancerization or host-tumor effects.

Adenocarcinoma↗

PubMed2004

Squamous cell carcinoma-related oncogene is highly expressed in developing, normal, and adenomatous adrenal tissue but not in aggressive adrenocortical carcinomas.

BACKGROUND: Our previous work has demonstrated squamous cell carcinoma-related oncogene (SCCRO) expression in adult murine adrenocortical tissue. The aim of this study was to assess patterns of SCCRO expression in the embryonic murine adrenal gland, and in normal and neoplastic human adrenocortical tissues in order to determine its role as a marker of differentiation in adrenocortical development and neoplastic progression. METHODS: Murine embryos were procured at developmental stages E8 to E18. A tissue microarray was constructed containing 38 normal, 39 adenomatous, and 87 carcinomatous human adrenocortical specimens. Immunohistochemistry for SCCRO was performed and its expression was graded in suitable tissues. RESULTS: SCCRO expression was detected in the murine adrenal cortex as early as E15 and persisted into the postnatal period. High-level SCCRO expression was identified in 94% of normal (32/34) and adenomatous (29/31) adrenocortical specimens but in only 63% (45/72) of adrenocortical carcinoma (ACC) specimens ( P = .001). Loss of SCCRO expression in primary ACC (13/34 (34%)) correlated with advanced stage ( P = .06), presence of M1 disease at presentation ( P = .03), and worse overall survival ( P = .006). CONCLUSIONS: SCCRO appears to be a marker of adrenocortical differentiation in both murine and human systems. SCCRO expression may be useful in distinguishing adrenocortical adenomas from ACC. Moreover, loss of SCCRO expression in primary ACC is associated with worse outcome and may be a marker of progressive dedifferentiation in these tumors.

Adrenal Cortex Neoplasms↗

PubMed2004

Current surgical opinion of computed tomography for acute appendicitis.

BACKGROUND: Appendiceal computed tomography (CTA) for the diagnosis of acute appendicitis (AA) has become popular, with a growing body of literature reporting excellent rates of sensitivity, specificity, and accuracy (S/S/A). However, several studies indicate that the true S/S/A of CTA is lower than the best results reported, especially if the white blood count is normal, the reader is inexperienced, or the study is obtained in the absence of surgical consultation. Thus, it is possible that skepticism of the value of CTA to diagnose AA may exist. Our objective was to determine the current knowledge of and attitudes regarding CTA among practicing surgeons. METHODS: Two thousand questionnaires were sent randomly to general surgeon Fellows of the American College of Surgeons. Questions detailed the surgeon's practice, experience, hospital characteristics, and opinion regarding the utility and use of CTA. The existence of a formal CTA protocol, its characteristics, and radiologist availability for CT interpretation were determined. Data were analyzed by x(2) with Fisher exact test, multiple-group x(2), and univariate ANOVA as appropriate. Results are reported as mean +/- SEM with significance accepted at p < 0.05. RESULTS: The response rate was 27%. Mean age was 51 +/- 1 years, 60% of respondents were general surgeons, and 9% were laparoscopic surgeons. Seventy-four percent of respondents believe the accuracy rate of CTA is less than the originally reported 98%; those who disbelieve are less likely to utilize CTA (p < 0.0001). Sixty-two percent of respondents believe CTA is over-utilized; 43% obtain CTA in </=25% of patients, and 62% obtain CTA in fewer than 50% of patients. Only 36% of respondents had access to CTA by protocol; those surgeons were more likely to know protocol details (p < 0.0001). Emergency medicine physicians order CTA most often (63%), and studies are most often interpreted by an attending radiologist (69%). CONCLUSIONS: Practicing surgeons are skeptical of the role of CTA for diagnosis of AA. Incorporation of CTA into practice is not widespread, perhaps because CTA by protocol is unavailable to most surgeons and because it is often obtained in the absence of surgical consultation.

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↗