Sam M. Wiseman

Meta-Analysis and Meta-Review of Thyroid Cancer Gene Expression Profiling Studies Identifies Important Diagnostic Biomarkers

PURPOSE An estimated 4% to 7% of the population will develop a clinically significant thyroid nodule during their lifetime. In many cases, preoperative diagnoses by needle biopsy are inconclusive. Thus, there is a clear need for improved diagnostic tests to distinguish malignant from benign thyroid tumors. The recent development of high-throughput molecular analytic techniques should allow the rapid evaluation of new diagnostic markers. However, researchers are faced with an overwhelming number of potential markers from numerous thyroid cancer expression profiling studies. MATERIALS AND METHODS To address this challenge, we have carried out a comprehensive meta-review of thyroid cancer biomarkers from 21 published studies. A gene ranking system that considers the number of comparisons in agreement, total number of samples, average fold-change and direction of change was devised. RESULTS We have observed that genes are consistently reported by multiple studies at a highly significant rate (P < .05). Comparison with a meta-analysis of studies reprocessed from raw data showed strong concordance with our method. CONCLUSION Our approach represents a useful method for identifying consistent gene expression markers when raw data are unavailable. A review of the top 12 candidates revealed well known thyroid cancer markers such as MET, TFF3, SERPINA1, TIMP1, FN1, and TPO as well as relatively novel or uncharacterized genes such as TGFA, QPCT, CRABP1, FCGBP, EPS8 and PROS1. These candidates should help to develop a panel of markers with sufficient sensitivity and specificity for the diagnosis of thyroid tumors in a clinical setting.

Caveolin-1 in tumor progression: the good, the bad and the ugly

Caveolin-1 (Cav1) is a multifunctional scaffolding protein with multiple binding partners that is associated with cell surface caveolae and the regulation of lipid raft domains. Cav1 regulates multiple cancer-associated processes including cellular transformation, tumor growth, cell migration and metastasis, cell death and survival, multidrug resistance and angiogenesis. However, Cav1 has been reported to impact both positively and negatively on various aspects of tumor progression and while reported to function as a tumor suppressor, it has also been identified as a poor prognostic factor in various human cancers. In this review, we survey the functional roles of Cav1 in cancer and argue that Cav1 function is interdependent on tumor stage and the expression of molecular effectors that impact on its role during tumor progression.

Phosphorylated Caveolin-1 Regulates Rho/ROCK-Dependent Focal Adhesion Dynamics and Tumor Cell Migration and Invasion

Rho/ROCK signaling and caveolin-1 (Cav1) are implicated in tumor cell migration and metastasis; however, the underlying molecular mechanisms remain poorly defined. Cav1 was found here to be an independent predictor of decreased survival in breast and rectal cancer and significantly associated with the presence of distant metastasis for colon cancer patients. Rho/ROCK signaling promotes tumor cell migration by regulating focal adhesion (FA) dynamics through tyrosine (Y14) phosphorylation of Cav1. Phosphorylated Cav1 is localized to protrusive domains of tumor cells and Cav1 tyrosine phosphorylation is dependent on Src kinase and Rho/ROCK signaling. Increased levels of phosphorylated Cav1 were associated with elevated GTP-RhoA levels in metastatic tumor cells of various tissue origins. Stable expression and knockdown studies of Cav1 in tumor cells showed that phosphorylated Cav1 expression stimulates Rho activation, stabilizes FAK association with FAs, and promotes cell migration and invasion in a ROCK-dependent and Src-dependent manner. Tyrosine-phosphorylated Cav1, therefore, functions as an effector of Rho/ROCK signaling in the regulation of FA turnover and, thereby, tumor cell migration and invasion. These studies define a feedback loop between Rho/ROCK, Src, and phosphorylated Cav1 in tumor cell protrusions, identifying a novel function for Cav1 in tumor metastasis that may contribute to the poor prognosis of some Cav1-expressing tumors.

Loss of BAF250a (ARID1A) is frequent in high‐grade endometrial carcinomas

Mutation of the ARID1A gene and loss of the corresponding protein BAF250a has recently been described as a frequent event in clear cell and endometrioid carcinomas of the ovary. To determine whether BAF250a loss is common in other malignancies, immunohistochemistry (IHC) for BAF250a was performed on tissue microarrays (TMAs) in more than 3000 cancers, including carcinomas of breast, lung, thyroid, endometrium, kidney, stomach, oral cavity, cervix, pancreas, colon and rectum, as well as endometrial stromal sarcomas, gastrointestinal stromal tumours, sex cord‐stromal tumours and four major types of lymphoma (diffuse large B cell lymphoma, primary mediastinal B cell lymphoma, mantle cell lymphoma and follicular lymphoma). We found that BAF250a loss is frequent in endometrial carcinomas but infrequent in other types of malignancies, with loss observed in 29% (29/101) of grade 1 or 2 and 39% (44/113) of grade 3 endometrioid carcinomas of the endometrium, 18% (17/95) of uterine serous carcinomas and 26% (6/23) of uterine clear cell carcinomas. Since endometrial cancers showed BAF250a loss, we stained whole tissue sections for BAF250a expression in nine cases of atypical hyperplasia and 10 cases of atypical endometriosis. Of the nine cases of complex atypical endometrial hyperplasia, all showed BAF250a expression; however, of 10 cases of atypical endometriosis (the putative precursor lesion for ovarian clear cell and endometrioid carcinoma), one case showed loss of staining for BAF250a in the atypical areas, with retention of staining in areas of non‐atypical endometriosis. This was the sole case that recurred as an endometrioid carcinoma, indicating that BAF250a loss may be an early event in carcinogenesis. Since BAF250a loss is seen in endometrial carcinomas at a rate similar to that seen in ovarian carcinomas of clear cell and endometrioid type, and is uncommon in other malignancies, we conclude that loss of BAF250a is a particular feature of carcinomas arising from endometrial glandular epithelium. Copyright

Diagnostic utility of galectin-3 in thyroid cancer.

Galectin-3 (Gal-3), which has received significant recent attention for its utility as a diagnostic marker for thyroid cancer, represents the most well-studied molecular candidate for thyroid cancer diagnosis. Gal-3 is a protein that binds to beta-galactosidase residues on cell surface glycoproteins and has also been identified in the cytoplasmic and nuclear compartment. This marker has been implicated in regulation of normal cellular proliferation and apoptosis, as well as malignant transformation and the metastasis of cancer cells. We here present a mechanistic review of Gal-3 and its role in cancer development and progression. Gal-3 expression studies in thyroid tissue and cytologic tumor specimens and their methodological considerations are also discussed in this article. Despite great variance in their methodology, the majority of immunohistochemical studies found that Gal-3 was differentially expressed in thyroid carcinoma compared with benign and normal thyroid specimens, suggesting that Gal-3 is a good diagnostic marker for thyroid cancer. Recent studies have also demonstrated improved methodological reliability. On the other hand, Gal-3 genomic expression studies have shown inconsistent results for diagnostic utility and are not recommended. Overall, the development of Gal-3 as a diagnostic marker for thyroid cancer represents a promising avenue for future study, and its clinical application could significantly reduce the number of diagnostic thyroid operations performed for cases of indeterminant fine needle aspiration biopsy cytology, and thus positively impact the current management of thyroid nodular disease.

Coexpression of the type 1 growth factor receptor family members HER-1, HER-2, and HER-3 has a synergistic negative prognostic effect on breast carcinoma survival

The clinical significance of coexpression of type 1 growth factor receptor (T1GFR) family members remains largely unknown. The objective of the current study was to determine the frequency and the possible prognostic effect of coexpression of HER‐1, HER‐2, HER‐3, and HER‐4 by breast carcinoma.

Anaplastic transformation of thyroid cancer: review of clinical, pathologic, and molecular evidence provides new insights into disease biology and future therapy.

Anaplastic thyroid cancer ranks among the most lethal of all human malignancies. Its rarity and rapidly fatal course have made it a difficult cancer to both study and treat. Unfortunately, there has been little progress in the management and control of this malignancy. Anaplastic transformation, or the intratumoral evolution of anaplastic carcinoma from pre‐existing differentiated thyroid cancer, has become a well‐accepted process, despite a limited understanding of its underlying mechanisms.

HER-2/neu Protein Expression and Gene Alteration in Stage I-IIIA Non-Small-Cell Lung Cancer: A Study of 140 Cases Using a Combination of High Throughput Tissue Microarray, Immunohistochemistry, and Fluorescent In Situ Hybridization

Regarding HER-2/ neu expression (gene or protein level) in lung cancer, several studies with inconsistent results have been recently reported, partially due to variable techniques used and/or heterogeneous populations examined. The objective of this study was to examine HER-2/ neu expression in a well-defined cohort of non–small-cell lung cancers (NSCLC) and in nonneoplastic lung tissue utilizing a combination of high-density tissue microarray, immunohistochemistry (IHC), and fluorescent in situ hybridization (FISH) under uniform test conditions. One hundred forty stage I-IIIA primary NSCLCs and 38 non-neoplastic lung samples were examined. IHC, using an FDA-approved Hercept monoclonal antibody kit, was performed and HER-2/ neu gene alteration was assessed by FISH. The association of expression of HER-2/ neu with clinicopathologic parameters was analyzed. Ninety-four percent of tumor samples (131/140) were fully interpretable after tissue processing. Twenty-five of them (19%) overexpressed (2+, 3+) HER-2/ neu, while 106 (81%) had no or weak expression. All thirty-four interpretable non-neoplastic lung samples were negative for HER-2/ neu alteration at protein and gene level. HER-2/ neu protein overexpression correlated well with HER-2/ neu gene amplification (r =.83, P < 0.001). HER-2/ neu overexpression was significantly associated with histologic subtype: 19 adenocarcinomas (19/82, 23%) versus 4 squamous cell carcinomas (4/44, 9%) overexpressed Her-2/ neu (P = 0.04). Statistical significance was observed between HER-2/ neu expression and tumor differentiation, with strong positive (3+) expression observed more frequently in poorly differentiated tumors (P = 0.01). Patients with HER-2/ neu abnormalities, particularly HER-2/ neu gene amplification, exhibited a shorter survival (P = 0.043). The statistically significant difference (P < 0.005) between HER-2/ neu alteration in tumor samples(25/131, 19%) and in the nonneoplastic tissue (0/34, 0%) implies that HER-2/ neu may have a role in the carcinogenesis of NSCLC. The findings provide evidence supporting the hypothesis that the HER-2/ neu receptor may represent a useful molecular target in the treatment of NSCLC. The significant association of HER-2/ neu expression and gene amplification with poorly differentiated carcinoma compared with well differentiated carcinoma suggests that HER-2/ neu may be involved in NSCLC tumor evolution. Patients with HER-2/ neu gene amplification and strong positive expression of HER-2/ neu protein showed a strong tendency toward shorter survival.

Altered E-cadherin and epidermal growth factor receptor expressions are associated with patient survival in lung cancer: a study utilizing high-density tissue microarray and immunohistochemistry

E-cadherin (E-cad) and epidermal growth factor receptor (EGFR) are important cell adhesion and signaling pathway mediators. This study aimed to assess their expression in lung adenocarcinoma (AdC) and squamous cell carcinoma (SCC) and their association with clinicopathologic variables. In all, 130 resectable lung cancers (stages I–IIIA) were studied using a high-density tissue microarray. Two to three cores from each case were arrayed into three blocks using a Beecher system. Immunohistochemistry was performed using an avidin–biotin complex method and monoclonal antibodies against E-cad and EGFR. Unequivocal membrane staining in >10% of tumor cells was considered as a positive expression of E-cad and EGFR. Markers expression and coexpression were analyzed against clinicopathologic variables (age, gender, smoking status, performance status, weight loss, histology, grade, stage, and lymph node involvement) and patient survival. There were 118, 126, and 115 cases that were fully assessable for E-cad, EGFR, and both markers, respectively. For E-cad, 65 cases (55%) were positive (+), 53 (45%) were negative (−); 23 cases of the negative group had only cytoplasmic staining. For EGRF, 43 cases (34%) were (+), and 83 (66%) were (−). There was no significant association between E-cad or EGFR, and any of the clinicopathologic variables except for an association between EGFR(+) and SCC histologic type. Both negative and cytoplasmic staining of E-cad correlated with shorter patient survival with P=0.008 and 0.002, respectively. EGFR expression did not correlate with patient survival; however, patients with E-cad(−)/EGFR(+) phenotype had poorer survival than those with E-cad(+)/EGFR(−) (P=0.026). Our study suggests that lung AdC and SCC may be stratified based on expression of E-cad and EGFR with the E-cad(−)/EGFR(+) expression having a worse disease outcome. Moreover, the cytoplasmic expression of E-cad may represent an altered localization of this protein in association with tumorigenicity.

Squamous Cell Carcinoma of the Head and Neck in Nonsmokers and Nondrinkers: An Analysis of Clinicopathologic Characteristics and Treatment Outcomes

Background: The objective of this study was to describe the clinicopathologic manifestations of disease and outcomes of treatment among individuals without a history of smoking tobacco or consuming alcohol who develop head and neck cancer.Methods: Of 1648 invasive head and neck cancer cases treated between 1970 and 2001 at Roswell Park Cancer Institute, 40 patients were identified as never having smoked tobacco or consumed alcohol during their lifetime. These cases were reviewed to gather data on multiple clinicopathologic variables.Results: Mean age at presentation of nonsmoker/nondrinker head and neck cancer patients was 60 years (range, 27 to 90 years), and 78% (n = 31) of the patients were women. The distributions of tumor sites were 75.0% oral cavity (n = 30), 20.0% oropharynx (n = 8), and 5.0% larynx (n = 2). Sixteen patients (40%) experienced a recurrence of disease during the follow-up period, and 10 patients (25.0%) developed a second primary tumor a median of 6 years after their initial diagnosis.Conclusions: The nonsmoker/nondrinker head and neck cancer patient tends to be elderly and female, have oral cavity primary tumors, and be predisposed to second primary tumor development.