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Background: Agents targeting programmed death-1 receptor (PD-1) and its ligand (PD-L1) are showing promising results in non-small-cell lung cancer (NSCLC). It is unknown whether PD-1/PD-L1 are differently expressed in oncogene-addicted NSCLC. Methods: We analysed a cohort of 125 NSCLC patients, including 56 EGFR mutated, 29 KRAS mutated, 10 ALK translocated and 30 EGFR/KRAS/ALK wild type. PD-L1 and PD-1 expression were assessed by immunohistochemistry. All cases with moderate or strong staining (2+/3+) in >5% of tumour cells were considered as positive. Results: PD-1 positive (+) was significantly associated with current smoking status ( P =0.02) and with the presence of KRAS mutations ( P =0.006), whereas PD-L1+ was significantly associated to adenocarcinoma histology ( P =0.005) and with presence of EGFR mutations ( P =0.001). In patients treated with EGFR tyrosine kinase inhibitors ( N =95), sensitivity to gefitinib or erlotinib was higher in PD-L1+ vs PD-L1 negative in terms of the response rate (RR: P =0.01) time to progression (TTP: P <0.0001) and survival (OS: P =0.09), with no difference in PD1+ vs PD-1 negative. In the subset of 54 EGFR mutated patients, TTP was significantly longer in PD-L1+ than in PD-L1 negative ( P =0.01). Conclusions: PD-1 and PD-L1 are differentially expressed in oncogene-addicted NSCLC supporting further investigation of specific checkpoint inhibitors in combination with targeted therapies.

Background: The aim of this study was to elucidate the prognostic impact of putative cancer stem cell markers CD133, CD166, CD44s, EpCAM, and aldehyde dehydrogenase-1 (ALDH1) in colorectal cancer. Methods: A tissue microarray of 1420 primary colorectal cancers and 57 normal mucosa samples was immunostained for CD133, CD166, CD44s, EpCAM, and ALDH1 in addition to 101 corresponding whole tissue sections. Invasive potential of three colorectal cancer cell lines was tested. Results: Differences between normal tissue and cancer were observed for all markers ( P <0.001). Loss of membranous CD166 and CD44s were linked to higher pT ( P =0.002, P =0.014), pN ( P =0.004, P =0.002), an infiltrating growth pattern ( P <0.001, P =0.002), and worse survival ( P =0.015, P =0.019) in univariate analysis only. Loss of membranous EpCAM expression was also linked to higher pN ( P =0.023) and infiltrating growth pattern ( P =0.005). The CD44s, CD166, and EpCAM expression were lost towards the invasive front. The CD44−/CD166− cells from three colorectal cancer cell lines exhibited significantly higher invasive potential in vitro than their positive counterparts. Conclusions: Loss, rather than overexpression, of membranous CD44s, CD166, and EpCAM is linked to tumour progression. This supports the notion that the membranous evaluation of these proteins assessed by immunohistochemistry may be representative of their cell adhesion rather than their intra-cellular functions.

BackgroundThe immune contexture predicts prognosis in human colorectal cancer (CRC). Whereas tumour-infiltrating CD8+ T cells and myeloid CD16+ myeloperoxidase (MPO)+ cells are associated with favourable clinical outcome, interleukin (IL)-17-producing cells have been reported to correlate with severe prognosis. However, their phenotypes and functions continue to be debated.ObjectiveTo investigate clinical relevance, phenotypes and functional features of CRC-infiltrating, IL-17-producing cells.MethodsIL-17 staining was performed by immunohistochemistry on a tissue microarray including 1148 CRCs. Phenotypes of IL-17-producing cells were evaluated by flow cytometry on cell suspensions obtained by enzymatic digestion of clinical specimens. Functions of CRC-isolated, IL-17-producing cells were assessed by in vitro and in vivo experiments.ResultsIL-17+ infiltrates were not themselves predictive of an unfavourable clinical outcome, but correlated with infiltration by CD8+ T cells and CD16+ MPO+ neutrophils. Ex vivo analysis showed that tumour-infiltrating IL-17+ cells mostly consist of CD4+ T helper 17 (Th17) cells with multifaceted properties. Indeed, owing to IL-17 secretion, CRC-derived Th17 triggered the release of protumorigenic factors by tumour and tumour-associated stroma. However, on the other hand, they favoured recruitment of beneficial neutrophils through IL-8 secretion and, most importantly, they drove highly cytotoxic CCR5+CCR6+CD8+ T cells into tumour tissue, through CCL5 and CCL20 release. Consistent with these findings, the presence of intraepithelial, but not of stromal Th17 cells, positively correlated with improved survival.ConclusionsOur study shows the dual role played by tumour-infiltrating Th17 in CRC, thus advising caution when developing new IL-17/Th17 targeted treatments.

Epithelial cell adhesion molecule (Ep-CAM; CD326) is used as a target by many immunotherapeutic approaches, but little data are available about Ep-CAM expression in major human malignancies with respect to level, frequency, tumour stage, grade, histologic tumour type and impact on survival. We analysed by immunohistochemical staining tissue microarrays with 4046 primary human carcinoma samples from colon, stomach, prostate and lung cancers for both frequency and intensity of Ep-CAM expression under highly standardised conditions. A total of 3360 samples were analysable. High-level Ep-CAM expression was observed in 97.7% ( n =1186) of colon, 90.7% of gastric ( n =473), and 87.2% of prostate cancers ( n =414), and in 63.9% of lung cancers ( n =1287). No detectable Ep-CAM staining was found with only 0.4% of colon, 2.5% of gastric, 1.9% of prostate cancers, and 13.5% of lung cancers. The only significant correlation of Ep-CAM expression with tumour grading was observed in colon cancer where high-level Ep-CAM expression on grade 3 tumours was down to 92.1% ( P <0.0001). Adenosquamous and squamous carcinomas of the lung had a lower percentage of high-level Ep-CAM expression compared to adenocarcinomas with 35.4 and 53.6%, respectively, and with 45.5 and 17.3% of tumours being Ep-CAM negative. With the exception of moderately differentiated colon carcinoma, where patients not expressing Ep-CAM on their tumours showed an inferior survival ( P =0.0014), correlation of Ep-CAM expression with survival did not reach statistical significance for any of the other cancer indications and subgroups. In conclusion, the data strongly support the notion that Ep-CAM is a prime target for immunotherapies in major human malignancies. This is because the most common human cancers show (i) a low frequency of Ep-CAM-negative tumours, (ii) a high frequency of Ep-CAM expression on cells of a given tumour, and (iii) for most cancers, an insignificant influence of tumour staging, grading and histology on Ep-CAM expression.

Background:A small subset (10–15%) of gastrointestinal stromal tumours (GISTs) lack mutations in KIT and PDGFRA (wild-type GIST). Recently, a novel BRAF exon 15 mutation (V600E) was detected in imatinib-naive wild-type high-risk intestinal GISTs (4%). However, the frequency and distribution of BRAF mutations within the spectrum of GISTs, and whether they might represent secondary events acquired during tumour progression, remain unknown.Methods:69 GISTs (39 KIT mutants, 2 PDGFRA mutants and 28 wild-type) were analysed for mutations in BRAF exon 15 and KRAS exon 2. To assess the stage at which these mutations might occur in GIST, a considerable number of incidental gastric (n = 23) and intestinal (n = 2) tumours were included.Results:BRAF mutations (V600E) were detected in 2 of 28 wild-type GISTs (7%), but in none of the 41 KIT/PDGFRA mutants. No KRAS mutation was detected. The two BRAF-mutated GISTs measured 4 mm in diameter and originated in the gastric body and the jejunum in two men (mean age, 76 years). Both tumours were mitotically inactive KIT-positive spindle-cell GISTs that were indistinguishable histologically from their more common KIT-mutated counterparts.Conclusion:BRAF mutations represent an alternative molecular pathway in the early tumorigenesis of a subset of KIT/PDGFRA wild-type GISTs and are per se not associated with a high risk of malignancy. Mutations in KIT, PDGFRA and BRAF were mutually exclusive in this study. Results from this and a previous study indicate that BRAF-mutated GISTs show a predilection for the small bowel (four of five tumours), but this needs further evaluation in larger studies.

Objective:To compare the independent prognostic effect of a panel of immunohistochemical protein markers in colorectal cancer (CRC) and determine their ranking among the established prognostic factors T stage, N stage, vascular invasion, tumour budding and tumour grade.Design:A tissue microarray of 1420 CRCs was immunostained for 23 markers and mismatch repair (MMR) proteins. Immunoreactivity was assessed semi-quantitatively. Receiver operating characteristic (ROC) curves were used to determine cut-off scores for tumour marker positivity. Survival time was investigated for each marker in multivariable analysis with T stage, N stage, vascular invasion, tumour budding and tumour grade. The hazard ratio (HR) was used to compare the prognostic effect of each marker on 5 year survival.Results:To the standard prognostic features, only six markers added independent prognostic information including receptor for hyaluronic acid mediated motility (RHAMM) (HR = 2.39 (1.88 to 3.05)), epidermal growth factor receptor (HR = 1.65 (1.31 to 2.09)), tumour infiltrating lymphocytes (HR = 0.7 (0.54 to 0.92)), urokinase plasminogen activator (HR = 1.38 (1.09 to 1.75)), Raf-1 kinase inhibitor protein (HR = 0.75 (0.58 to 0.96)) and mammalian sterile 20-like kinase 1 (MST1) (HR = 0.75 (0.58 to 0.95). Diffuse (>90% staining) expression of RHAMM ranked above T stage, vascular invasion, tumour budding and tumour grade in terms of adverse prognostic significance and was associated with distant metastasis (p = 0.012) and with worse outcome in patients with metastatic disease (p = 0.031).Conclusions:The strong adverse effect of RHAMM on outcome in addition to its position within the hierarchy of well-established prognostic factors suggest that RHAMM should be considered a more important prognosticator than tumour grade, tumour budding and vascular invasion in patients with CRC.

The aim of this study was to determine the predictive and prognostic value of epidermal growth factor receptor (EGFR) expression in rectal cancers treated with preoperative high-dose rate brachytherapy and in mismatch-repair (MMR)-proficient colorectal cancers (CRCs), respectively. We validate the use of receiver operating characteristic (ROC) curve analysis to select cutoff scores for EGFR overexpression for the end points studied. Immunohistochemistry (IHC) for EGFR was performed on 82 rectal tumour biopsies and 1197 MMR-proficient CRCs using a tissue microarray. Immunoreactivity was scored as the percentage of positive tumour cells by three pathologists and the inter-observer reliability was assessed. ROC curve-derived cutoffs were used to analyse the association of EGFR overexpression, tumour response and several clinicopathological features including survival. The scoring method was found to be reproducible in rectal cancer biopsies and CRCs. The selected cutoff scores from ROC curve analysis for each clinicopathological feature were highly consistent among pathologists. EGFR overexpression was associated with response to radiotherapy ( P -value <0.001) and with worse survival time ( P -value <0.001). In multivariate analysis, EGFR overexpression was independently associated with adverse prognosis ( P -value <0.001). Epidermal growth factor receptor is a predictive marker of response to preoperative radiotherapy and an independent adverse prognostic factor CRC.

Background: Expression of mucin antigen MUC1 and down regulation of MUC2 are associated with adverse prognosis in colorectal cancer (CRC), but their prognostic significance with respect to differing DNA mis- match repair (MMR) status is poorly understood. Objective: To determine the prognostic significance of MUC1 and MUC2 in CRC with different MMR statuses. Methods: Using the tissue microarray (TMA) technique, a series of 1420 unselected, non-consecutive CRC resections was subdivided into three groups: (1) MMR-proficient; (2) MLH1-negative; and (3) presumed hereditary non-polyposis colon cancer (HNPCC). Immunohistochemical analysis of MUC1 and MUC2 expression (>0%) and loss (0%) was performed, and the results were correlated with clinicopathological parameters. Results: In MMR-proficient CRC, MUC1 expression was more frequently found in tumours with higher tumour stage (p = 0.004) and higher tumour grade (p = 0.041) and loss of MUC2 was associated with higher tumour stage (p = 0.028), node stage (p = 0.001), presence of vascular invasion (p = 0.028) and worse survival (p = 0.034). In MLH1-negative CRC, MUC2 loss was associated with the presence of lymph node metastasis (p = 0.028) and worse survival (p = 0.015), but there was no association between MUC1 expression and clinicopathological features. In presumed HNPCC, MUC1 expression and MUC2 loss were not associated with clinicopathological parameters. Conclusions: Mucins have a prognostic significance in sporadic CRC, but not in hereditary CRC. Loss of MUC2 is an adverse prognostic factor in MMR-proficient and MLH1-negative CRC, whereas MUC1 expression is associated with tumour progression in MMR-proficient CRC only.

Aims: To assess the value of homeobox protein CDX-2 expression in the distinction between primary ovarian carcinomas and carcinomas metastatic to the ovary. Methods: CDX-2 expression was assessed by immunohistochemistry in 120 serous, 68 endometrioid, 24 clear cell, and 16 mucinous carcinomas of the ovary. In addition, CDX-2 immunoreactivity was investigated in 20 metastases from adenocarcinomas to the ovary (15 of colorectal, two of gastric, one of appendiceal, one of pancreatic, and one of cervical origin) and their corresponding primary tumours. Results: Almost all of the primary ovarian carcinomas lacked immunoreactivity for CDX-2. In contrast, 14 of the 16 metastases to the ovary from intestinal primaries showed CDX-2 immunoexpression. Conclusion: CDX-2 is a useful marker for differentiating primary ovarian carcinoma from carcinomas metastatic to the ovary.

CDX2 is a homeobox domain-containing transcription factor that is important in the development and differentiation of the intestines. Based on recent studies, CDX2 expression is immunohistochemically detectable in normal colonic enterocytes and is retained in most, but not all, colorectal adenocarcinomas. CDX2 expression has also been documented in a subset of adenocarcinomas arising in the stomach, esophagus and ovary. In this study, we examined CDX2 expression in a series of large tissue microarrays representing 4652 samples of normal and neoplastic tissues. Strong nuclear staining for CDX2 was observed in 97.9% of 140 colonic adenomas, 85.7% of 1109 colonic adenocarcinomas overall and 81.8% of 55 mucinous variants. There was no significant difference in the staining of well-differentiated (96%) and moderately differentiated tumors (90.8%, P=0.18), but poorly differentiated tumors showed reduced overall expression (56.0%, P<0.000001). Correspondingly, there was an inverse correlation between CDX2 expression and tumor stage, with a significant decrease in staining between pT2 and pT3 tumors (95.8 vs 89.0%, P<0.012), and between pT3 and pT4 tumors (89.0 vs 79.8%, P<0.016). Analysis of 140 locally advanced, CDX2-positive colorectal adenocarcinomas coarrayed with their matching lymph node metastases revealed that expression of this marker was retained in 82.1% of the metastases. Consistent with previous reports, CDX2 staining was observed in gastric adenocarcinomas (n=71), more commonly in the intestinal-type than the diffuse-type (28.9 vs 11.5%, P<0.05). Occasional ovarian carcinomas were positive for CDX2, including mucinous (10.5%), endometrioid (9.3%) and serous variants (2%), but expression was either very rare or absent in primary carcinomas of the lung, breast, thyroid, pancreas, liver, gallbladder, kidney, endometrium and urinary bladder. A low frequency of CDX2 expression in pancreatic and biliary carcinomas observed on the microarrays was pursued further by comparing these tumors with ampullary adenocarcinomas on conventional sections. Ampullary adenocarcinomas were more commonly positive for CDX2 (19/24, 79%) than cholangiocarcinomas (1/11, 9%) and pancreatic carcinomas (3/20, 15%). In summary, CDX2 is a sensitive and specific marker for colorectal adenocarcinoma, although its expression is decreased among higher grade and stage tumors, and it is not invariably present in metastases from positive primaries. CDX2 may also be helpful in distinguishing adenocarcinomas of the ampulla from those arising in the pancreas and biliary tree.