Human papilloma virus genome is rare in North American non-small cell lung carcinoma patients.

The reported prevalence for presence of human papillomavirus (HPV) genome in lung cancer varies across the world, and limited data are available for North America. P16 immunostaining is used as a surrogate marker for the presence of HPV in cervical and head and neck cancers. In non-small cell lung carcinoma (NSCLC), the association between P16 protein overexpression and HPV remains unclear. We investigated the presence of HPV genome by in situ hybridization (ISH) and polymerase chain reaction (PCR) and P16 or Rb protein expression by immunohistochemistry (IHC) in 336 surgically resected primary NSCLC: 204 adenocarcinoma (AdC) and 132 squamous cell carcinoma (SqCC). HPV genome was detected in 5 (1.5%) of 336 tumors studied by both ISH and PCR; all of them were typed as HPV16 and found in SqCC (3.8%). Despite being solitary tumors and clinically considered as primary lung cancers, all 5 patients had past history of HPV associated squamous cell carcinomas of other organ sites, thus highly suggestive of being metastases. P16 immunostaining was found in 137 (40.8%) tumors, with 109 (32.4%) showing high level expression. All HPV positive (+) cases showed P16 high expression. P16 and Rb protein expressions were inversely correlated (P<0.001), suggesting that the high P16 expression is largely driven by non-HPV loss of Rb protein expression. We conclude that HPV is not or rarely associated with NSCLC in Canadian and most likely North American patients, and P16 immunostaining is not a surrogate marker for its presence.

Loss of phosphatase and tensin homolog protein expression is an independent poor prognostic marker in lung adenocarcinoma.

INTRODUCTION: Phosphatase and tensin homolog (PTEN) has been established as a tumor suppressor gene with an important role in regulating the phosphatidylinositol-3-kinase/AKT antiapoptotic and survival pathway. The prognostic role of PTEN in non-small-cell lung carcinoma has not been evaluated completely in the context of other molecular information. METHODS: Tissue microarrays containing 152 resected non-small-cell lung cancer specimens were used to investigate PTEN and p53 by immunohistochemistry and PTEN by fluorescence in situ hybridization. DNA was isolated and subjected to mutational profiling using the Sequenom Oncocarta v1.0 panel. Clinicopathological features were correlated with PTEN expression, gene copy number, and mutation status. RESULTS: PTEN staining was absent in 63 (41.4%) of the cases. Significantly more squamous cell carcinomas compared with adenocarcinomas demonstrated loss of (negative) PTEN staining (26 of 44 [59%] versus 32 of 94 [34%]; p = 0.009). PTEN gene copy deletion was present in only seven of 124 evaluable cases (5.6%); all deleted cases were immunohistochemistry negative. In univariate and multivariate (MV) analyses adjusted for sex, age, histology, and stage, loss of PTEN protein expression was associated with significantly shorter disease-free survival (MV hazard ratio: 1.78, 95% confidence interval: 1.01-3.14, p = 0.048), whereas no significant associations were seen with p53 or KRAS and epidermal growth factor receptor (EGFR) mutation status. Importantly, the prognostic value of absent PTEN staining was limited to adenocarcinomas, with MV disease-free survival hazard ratio of 2.68 (95% confidence interval: 1.35-5.32, p = 0.005), whereas no such association was seen in squamous cell carcinomas. CONCLUSION: Absence of PTEN protein expression is an independent prognostic marker in early-stage resected lung adenocarcinoma.

Characterization of lymphomas developing in immunodeficient mice implanted with primary human non-small cell lung cancer.

INTRODUCTION: Xenograft models of epithelial malignancies potentially have greater correlation with clinical end points. We implanted 153 primary non-small cell lung carcinomas into non-obese diabetic-severe combined immunodeficient mice to develop primary lung cancer xenografts. Sixty-three xenografts formed. However, in 19 implantations, tumors consisted of a lymphocyte proliferation without a carcinoma component. We further characterized these lymphomas to determine clinicopathological features associated with their formation. METHODS: Lymphomas were investigated morphologically and by silver in situ hybridization to determine their species of origin. Characterization both of the xenograft lymphomas and the primary NSCLCs from which they were derived included immunohistochemistry for lymphoma markers and Epstein Barr virus Early RNA (EBER) by in situ hybridization. DNA was profiled using the MassARRAY platform; EML4-ALK translocations and lymphocyte infiltration were assessed in the primary tumor. Lymphoma formation was correlated with patient and primary tumor characteristics and survival. RESULTS: The lymphocytic tumors were EBER positive, human diffuse large B-cell lymphomas (DLBCLs). Significantly more DLBCLs that formed in mice arose in primary lung adenocarcinomas and in epithelial growth factor receptor mutant never smokers. DLBCL formation was not associated with the degree of tumor-infiltrating lymphocytes or EBER-positive lymphocytes in the primary NSCLCs. Patients whose tumors developed DLBCL had longer disease-free survival compared with patients whose tumors formed epithelial xenografts (hazard ratio: 0.44; 95% confidence interval: 0.18 -1.06, Wald p = 0.07), regardless of genotype. CONCLUSION: We hypothesize that mechanisms involved in the active suppression of viral antigens may also be involved in the suppression of tumor antigens, and may have resulted in the observed favorable clinical outcome.

The ability to form primary tumor xenografts is predictive of increased risk of disease recurrence in early-stage non-small cell lung cancer.

PURPOSE: Primary tumor xenografts (PTXG) established directly from patients' primary tumors in immunosuppressed animals might represent the spectrum of histologic complexity of lung cancers better than xenografts derived from established cell lines. These models are important in the study of aberrant biological pathways in cancers and as preclinical models for testing new therapeutic agents. However, not all primary tumors engraft when implanted into immunosuppressed mice. We have investigated factors that may influence the ability of primary non-small cell lung cancer (NSCLC) to form xenografts and their association with clinical outcome. EXPERIMENTAL DESIGN: Tumor fragments from patients undergoing curative surgery were implanted into NOD-SCID (nonobese diabetic-severely combined immunodeficient) mice within 24 hours of surgery. Patient characteristics for tumors that engrafted (XG) and did not engraft (no-XG) were compared. Patient tumor DNA was profiled for the presence of 238 known mutations in 19 cancer-associated genes by using the MassARRAY platform. RESULTS: Xenografts were established and passaged successfully from 63 of 157 (40%) implanted NSCLCs. Tumor factors associated with engraftment included squamous histology, poor differentiation, and larger tumor size. Significantly fewer EGFR (epidermal growth factor receptor)-mutated tumors engrafted (P = 0.03); conversely, more K-RAS-mutated tumors engrafted (P = 0.05). In multivariate analysis including age, sex, stage, and mutation, patients with XG tumors had significantly shorter disease-free survival compared with no-XG patients (hazard ratio: 7.0, 95% CI: 3.1-15.81; P < 0.000003). CONCLUSION: PTXGs closely mirror the histology and molecular profiles of primary tumors and therefore may serve as important preclinical models. Tumors that engraft are biologically more aggressive and may be more representative of cancers with a higher propensity to relapse after surgery.

Sporadic clear cell renal cell carcinoma with diffuse cytokeratin 7 immunoreactivity.

AIMS: Clear cell renal cell carcinoma (CRCC) with diffuse immunoreactivity for CK7 is described. METHODS: All cases of CRCC, measuring 20 mm or less in diameter over a period of 10 years, were examined. Areas of regenerative epithelial cell nests (REC) were also examined. RESULTS: Fifteen specimens containing 29 nodules were diagnosed as CRCC due to the characteristic clear cytoplasm. Of these 29 nodules, 21 showed diffuse CK7 positivity while eight showed CK7 negativity. The CK7 positive CRCC measured less than 16 mm and contained varying proportions of tumour cells with chromophil cytoplasm. Architecturally, CK7 positive CRCC consisted of cysts and solid cell nests with tubulo-acinar formations or papillary formations. Immunostaining for AMACR, CD10 and RCC showed negative or focal reactivity in the CK7 positive CRCC, frequently positive reactivity in CK7 negative CRCC and negative reactivity in REC which also displayed strong CK7 reactivity. The ten patients with 21 CK7 positive CRCC developed no metastatic disease over a follow up time that ranged from 1 to 10 years (mean of 3 years). CONCLUSIONS: CRCC characterised by diffuse CK7 positivity represents a distinct type of CRCC with characteristic histopathological and immunohistochemical features.

Oncocytic papillary renal cell carcinoma with solid architecture: mimic of renal oncocytoma.

Papillary renal cell carcinoma (PRCC) can display extensive areas of solid and non-papillary architecture and extensive areas with oncocytic cytoplasm. Eleven oncocytic renal cell neoplasms (ORCN) with histopathological features posing a diagnostic problem between renal cell carcinoma (RCC) with oncocytic features and renal oncocytoma (RO) were identified. The neoplasms were well circumscribed or encapsulated tumors with solid and diffuse growth pattern. Very occasional papillae were seen in four and tumoral necrosis in two of 11. Six ORCN displayed a CD117+/progesterone receptor (PR)+ immunophenotype (feature shared by RO) and five tumors displayed a CD117-/PR- immunophenotype (feature shared by RCC). The CD117-/PR- ORCN also displayed alpha-methylacyl-coenzyme A racemase and RCC antigen reactivity as well as varying reactivity for cytokeratin 7, vimentin and CD10 (features of oncocytic PRCC). These five cases had tumor sizes ranging from 1 to 6 cm. Two patients in the latter group developed progression of the disease with metastases. In conclusion, oncocytic PRCC with solid architecture is a rare type of RCC. The carcinoma often poses differential diagnostic problems with RO and has similar immunohistochemical properties to the common type of PRCC. Cytogenetic and molecular studies have not been performed yet for this variant of RCC.

Cytohistopathologic hybrid renal cell carcinoma with papillary and clear cell features.

Clear cell (CRCC) and papillary (PRCC) renal cell carcinomas (RCC) are the two most frequent subtypes of RCC. In this study, we studied RCC which displayed a hybrid morphology with areas of PRCC and CRCC or which contained papillary structures with clear cell changes (CCC). Consecutive cases of RCC collected over a 12-year period were reviewed to identify RCC with papillary structures and a possible admixture between CRCC and non-oncocytic PRCC. Special stains for glycogen and immunostaining for cytokeratin 7 were applied to sections containing both areas of classical PRCC and PRCC with CCC. Of the total of 541 RCC retrieved, there were 68 non-oncocytic RCC having papillary structures that could be grouped into: (a) group 1 (15 cases), CRCC with areas of papillary formation; (b) group 2a (9 cases), PRCC with extensive CCC with areas of foamy epithelial cells or macrophages; (c) group 2b (18 cases), RCC with areas of classical PRCC with focal CCC; and (d) group 3 (26 cases), RCC with features of groups 2a and 2b and containing areas of classical CRCC. There was a high rate (12/68) of sarcomatous transformation in the study cases. Groups 2 and 3 were associated with a higher rate of vascular invasion, distant metastasis, and mortality than classical PRCC and a higher rate of lymph node metastasis than CRCC. Our study identifies two groups of RCC (referred to as groups 2 and 3) that exhibit characteristic cytohistopathologic hybrid features that set them apart from classical RCC. This type of hybrid tumor seems to be associated with a more aggressive biologic behavior, and its recognition may facilitate the classification of RCC with ambiguous morphology.