Typing somatostatin receptor expression in neuroendocrine tumors is of relevance to target somatostatin analogue-based diagnostic approach and treatment. The expanding use of immunohistochemistry to detect somatostatin receptors is to date not paralleled by an accurate methodological setting and standardized interpretation of the results. A multicentric study was designed to compare somatostatin receptor immunohistochemical expression with in vivo scintigraphic data and verify its usefulness in the clinical management of neuroendocrine tumors. After methodological setting by testing different somatostatin receptor antibodies, 107 cases of neuroendocrine tumors with available somatostatin receptor scintigraphy data and pathological material were retrospectively analyzed for somatostatin receptor types 2A, 3 and 5 immunohistochemical expression, and compared with scintigraphic images and, whenever available, with the clinical response to somatostatin analogue treatment. Restricting 'positive cases' to the presence of a membrane pattern of staining, an overall somatostatin receptor type 2A immunohistochemistry/somatostatin receptor scintigraphy agreement of 77% (v 2 test Po0.0001) was reached. Lower concordance ratios were detected in preoperative and metastatic tumor samples, possibly as a consequence of somatostatin receptor expression heterogeneity. Pure somatostatin receptor type 2A cytoplasmic staining showed poor correlation with somatostatin receptor scintigraphy (54% concordance rate). The immunohistochemical detection of somatostatin receptor types 3 and 5, which showed almost exclusively a cytoplasmic pattern, did not improve the concordance with scintigraphic data. In a pilot series, somatostatin receptor type 2A immunohistochemistry correlated with clinical response in 75% of cases. In conclusion, we propose a scoring system for somatostatin receptor type 2A immunohistochemistry in neuroendocrine tumors correlated with in vivo data, based on the evidence that only membrane (rather that cytoplasmic) staining should be considered for a reliable, standardized and clinically relevant report.

Lung neuroendocrine tumors are catalogued in four categories by the World Health Organization (WHO 2004) classification. Its reproducibility and prognostic efficacy was disputed. The WHO 2010 classification of digestive neuroendocrine neoplasms is based on Ki67 proliferation assessment and proved prognostically effective. This study aims at comparing these two classifications and at defining a prognostic grading system for lung neuroendocrine tumors. The study included 399 patients who underwent surgery and with at least 1 year follow-up between 1989 and 2011. Data on 21 variables were collected, and performance of grading systems and their components was compared by Cox regression and multivariable analyses. All statistical tests were two-sided. At Cox analysis, WHO 2004 stratified patients into three major groups with statistically significant survival difference (typical carcinoid vs atypical carcinoid (AC), PZ0.021; AC vs large-cell/ small-cell lung neuroendocrine carcinomas, P!0.001). Optimal discrimination in three groups was observed by Ki67% (Ki67% cutoffs: G1 !4, G2 4-!25, G3 R25; G1 vs G2, PZ0.021; and G2 vs G3, P%0.001), mitotic count (G1 %2, G2 O2-47, G3 O47; G1 vs G2, P%0.001; and G2 vs G3, P%0.001), and presence of necrosis (G1 absent, G2 !10% of sample, G3 O10% of sample; G1 vs G2, P%0.001; and G2 vs G3, P%0

Next-generation sequencing was applied to a relatively large retrospective series of MPM using formalin-fixed, paraffin-embedded archival material. Our results indicate a complex mutational landscape with a higher number of genetic variations in the p53/DNA repair and phosphatidylinositol 3-kinase pathways, some of them with prognostic value.

BACKGROUND: Histopathological subtyping of nonsmall cell lung cancer (NSCLC) is currently relevant in treatment decision because of a differential activity of specific therapeutic agents. Immunohistochemistry highlights cell differentiation lineages and, in this study, it was applied to maximize the proportion of accurately subtyped NSCLC not otherwise specified (NOS) on fine-needle aspiration cytology (FNAC) samples. METHODS: Cell blocks from 103 FNAC samples with a morphological diagnosis of NSCLC-NOS were immunostained for cytokeratin (CK) 7, CK5, TTF1, and p63, whereas p40, napsin A (Naps-A), and desmocollin-3 (DSC-3) were only assessed in a subgroup of cases with discordant (CK7 and TTF1þ for nonsquamous, CK5 and p63þ for squamous) findings. Results were correlated with surgical specimens evaluated by morphology alone. RESULTS: Thirty-seven (36%) tumors with CK7/TTF1þ and CK5/p63À corresponded to 35 cases of adenocarcinoma (ADC) and 2 cases of large cell carcinoma, whereas 9 (9%) cases with the reverse immunoprofile were squamous cell carcinoma (SQCC) at surgery (P < .001). Although the remaining 57 cases had different marker combinations, a correlation was found with ADC histology for TTF1þ samples (independent of other markers) and with SQCC for p63þ/TTF1À immunophenotype (P < .001). p40 was never expressed in p63þ ADC, whereas Naps-A was restricted to ADC and DSC-3 to SQCC lineage. The percentage of unclassified NSCLC-NOS decreased from 36% to 14%. Combinations of 2 antibodies (TTF1/DSC-3 or p63/Naps-A) in the same section allowed diagnostic optimization in scant cytological samples. CONCULSIONS: This 4-antibody panel approach may contribute to refine lung cancer classification in FNAC cell blocks, remarkably reducing the NSCLC-NOS diagnostic category. Cancer 2011;117:3416-

In patients with MPM treated with P-based chemotherapy, low TS protein levels are predictive of improved TTP and OS. The role of TS assessment is worth of prospective validation in future studies on MPM.