Intrapatient Tumor Heterogeneity in IHC Interpretation Using PD-L1 IHC 22C3 pharmDx.

Tumor heterogeneity may impact immunohistochemical (IHC) interpretation, thus potentially affecting decision making by treating oncologists for cancer patient management. Programmed cell death ligand-1 (PD-L1) IHC 22C3 pharmDx is a companion diagnostic used as an aid in identifying patient eligibility for treatment with pembrolizumab (KEYTRUDA). This study aims to investigate tumor heterogeneity impact on IHC staining when evaluating PD-L1 expression using PD-L1 IHC 22C3 pharmDx. The effect of tumor heterogeneity was evaluated based on the PD-L1 diagnostic status of PD-L1 IHC 22C3 pharmDx stained tumor tissue sections at relevant diagnostic cutoffs for non-small cell lung carcinoma, gastric or gastroesophageal junction adenocarcinoma, urothelial carcinoma, head and neck squamous cell carcinoma, esophageal cancer and triple negative breast cancer. Overall agreement for the PD-L1 diagnostic status was assessed for each tumor type within a given specimen block (Intra-Block), between specimen blocks from the same surgical resection (Intra-Case), and between intrapatient primary and metastatic specimens. Intrablock and intracase point estimates were above 75%, and primary versus metastatic point estimates were above 50%. The results suggest that PD-L1 expression is consistent across cut sections through a minimum of 150 µm within a tissue block and between blocks from the same surgical resection and is significantly maintained across primary and metastatic blocks from the same patient despite changes to the tissue microenvironment. These data provide confidence for histopathologists and oncologists that evaluation of PD-L1 expression at clinically relevant cutoffs is reproducible among different assessments (or samplings) of a single tumor specimen.

Enteric Glia Play a Critical Role in Promoting the Development of Colorectal Cancer.

Enteric glia are a distinct population of peripheral glial cells in the enteric nervous system that regulate intestinal homeostasis, epithelial barrier integrity, and gut defense. Given these unique attributes, we investigated the impact of enteric glia depletion on tumor development in azoxymethane/dextran sodium sulfate (AOM/DSS)-treated mice, a classical model of colorectal cancer (CRC). Depleting GFAP+ enteric glia resulted in a profoundly reduced tumor burden in AOM/DSS mice and additionally reduced adenomas in the ApcMin /+ mouse model of familial adenomatous polyposis, suggesting a tumor-promoting role for these cells at an early premalignant stage. This was confirmed in further studies of AOM/DSS mice, as enteric glia depletion did not affect the properties of established malignant tumors but did result in a marked reduction in the development of precancerous dysplastic lesions. Surprisingly, the protective effect of enteric glia depletion was not dependent on modulation of anti-tumor immunity or intestinal inflammation. These findings reveal that GFAP+ enteric glia play a critical pro-tumorigenic role during early CRC development and identify these cells as a potential target for CRC prevention.

Gastrointestinal Tract Vasculopathy: Clinicopathology and Description of a Possible "New Entity" With Protean Features.

Noninfectious gastrointestinal (GI) vasculopathic disorders are rare and are often overlooked in histopathologic examination or when forming differential diagnoses due to their rarity. However, involvement of the GI tract may lead to serious complications, including ischemia and perforation. Since awareness of the types of vasculopathy that may involve the GI tract is central to arriving at a correct diagnosis, we reviewed our institutional experience with GI tract vasculopathy in order to enhance diagnostic accuracy of these rare lesions. We report the clinical and histologic features of 16 cases (excluding 16 cases of immunoglobulin A vasculitis) diagnosed over a 20-year period. Of the 16 patients, 14 presented with symptoms related to the GI vasculopathy (including 2 presenting with a mass on endoscopic examination). The remaining 2 patients presented with incarcerated hernia and invasive adenocarcinoma. The vasculopathy was not associated with systemic disease and appeared limited to the GI tract in 8 patients. Eight had associated systemic disease, but only 6 had a prior diagnosis. The underlying diagnoses in these 6 patients included systemic lupus erythematosus (1), dermatomyositis (2), rheumatoid arthritis (1), eosinophilic granulomatosis with polyangiitis (1), and Crohn disease (1). One patient with granulomatous polyangiitis and 1 patient with systemic lupus erythematosus initially presented with GI symptoms. The 8 cases of isolated GI tract vasculopathy consisted of enterocolic lymphocytic phlebitis (4), idiopathic myointimal hyperplasia of the sigmoid colon (1), idiopathic myointimal hyperplasia of the ileum (1), granulomatous vasculitis (1), and polyarteritis nodosa-like arteritis (1). Isolated GI tract vasculopathy is rare, but appears to be almost as common as that associated with systemic disease. The chief primary vasculopathies are enterocolic lymphocytic colitis and idiopathic myointimal hyperplasia. Although the latter occurs predominantly in the left colon, rare examples occur in the small bowel and likely represent a complex, more protean disorder.

Normalizing Microbiota-Induced Retinoic Acid Deficiency Stimulates Protective CD8(+) T Cell-Mediated Immunity in Colorectal Cancer.

Although all-trans-retinoic acid (atRA) is a key regulator of intestinal immunity, its role in colorectal cancer (CRC) is unknown. We found that mice with colitis-associated CRC had a marked deficiency in colonic atRA due to alterations in atRA metabolism mediated by microbiota-induced intestinal inflammation. Human ulcerative colitis (UC), UC-associated CRC, and sporadic CRC specimens have similar alterations in atRA metabolic enzymes, consistent with reduced colonic atRA. Inhibition of atRA signaling promoted tumorigenesis, whereas atRA supplementation reduced tumor burden. The benefit of atRA treatment was mediated by cytotoxic CD8(+) T cells, which were activated due to MHCI upregulation on tumor cells. Consistent with these findings, increased colonic expression of the atRA-catabolizing enzyme, CYP26A1, correlated with reduced frequencies of tumoral cytotoxic CD8(+) T cells and with worse disease prognosis in human CRC. These results reveal a mechanism by which microbiota drive colon carcinogenesis and highlight atRA metabolism as a therapeutic target for CRC.

Preoperative Multidetector CT Diagnosis of Extrapancreatic Perineural or Duodenal Invasion Is Associated with Reduced Postoperative Survival after Pancreaticoduodenectomy for Pancreatic Adenocarcinoma: Preliminary Experience and Implications for Patient Care.

Purpose To test the hypothesis that patients with pancreatic adenocarcinoma who otherwise are viewed to have resectable disease but have preoperative findings of extrapancreatic perineural invasion (EPNI) and/or duodenal invasion at multidetector computed tomography (CT) have reduced postoperative survival after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC). Materials and Methods This study was approved by the institutional review board and complied with HIPAA. The authors retrospectively evaluated 76 consecutive patients with PDAC who underwent preoperative multidetector CT and subsequent pancreaticoduodenectomy. Two radiologists blinded to surgical pathology results and clinical outcome evaluated multidetector CT images for evidence of EPNI and duodenal invasion; discrepancies were resolved by consensus. Also determined for each patient were resected lymph node status, tumor size, surgical margin status, time to progression, and time to death. Data were assessed with the Goodman-Kruskal gamma for correlations among indicators and the log-rank test, Kaplan-Meier estimates, and multivariate Cox proportional hazards regression for survival analysis. Results In univariate analysis, duodenal invasion and/or EPNI on preoperativemultidetector CT images was associated with significantly decreased progression-free survival (P < .0001) and overall survival (P = .0013), and the clinical indicators (lymph node status, tumor size, and surgical margin status) as well as duodenal invasion and/or EPNI showed correlation with each other. In multivariate regression that included multidetector CT findings as well as the three traditional clinical indicators, only duodenal invasion and/or EPNI showed significant independent association with reduction in both modes of survival (P < .0001 and P = .014, respectively). Interobserver agreement was substantial with respect to EPNI and duodenal invasion (κ = 0.691 and 0.682, respectively). Conclusion Patients with evidence of EPNI and/or duodenal invasion on preoperative multidetector CT images have significantly reduced survival after pancreaticoduodenectomy for PDAC. © RSNA, 2016.

Intraductal Papillary Mucinous Neoplasms Often Contain Epithelium From Multiple Subtypes and/or Are Unclassifiable.

Pancreatic intraductal papillary mucinous neoplasms (IPMNs) are subclassified into gastric, intestinal, pancreatobiliary, and oncocytic subtypes based on histologic features. The WHO classification scheme suggests use of immunohistochemical stains to help subtype IPMNs with ambiguous histology. Seventy-two pancreatic IPMN resections between 2008 and 2014 were retrospectively evaluated. Immunohistochemistry for CDX2, MUC2, and MUC5AC was performed on cases where the histologic subtype could not be determined on routine hematoxylin and eosin (H&E) sections. There were 41 gastric (57%), 8 intestinal (11%), 4 pancreatobiliary (6%), and 1 oncocytic (1%) IPMNs. Eighteen (25%) IPMNs were either unclassifiable due ambiguous morphology or contained distinct epithelium from >1 subtype (i.e., "mixed"). Two IPMNs initially unclassifiable strictly by H&E morphology were definitively classified as intestinal after positive immunohistochemical staining with CDX2, MUC2, and MUC5AC. Immunohistochemistry for another 7 IPMNs unclassifiable by H&E did not indicate a clear subtype and often contained discordant results (e.g., discordant CDX2 and MUC2 staining). In our experience, a considerable number of IPMNs are either unclassifiable or contain epithelium from >1 subtype. Furthermore, among those IPMNs initially unclassifiable by H&E morphology, application of immunohistochemical stains to aid in subtyping allow for definite classification in only a small subset of cases. These data, when taken in context with the significant ranges in the reported prevalence of specific histologic subtypes, suggest that accurate IPMN subtyping is poorly reproducible in up to 25% of cases, and in these problematic cases, immunohistochemistry adds little value.

MDCT Diagnosis of Perineural Invasion Involving the Celiac Plexus in Intrahepatic Cholangiocarcinoma: Preliminary Observations and Clinical Implications.

OBJECTIVE: The purpose of this study was to test the hypothesis that soft-tissue infiltration along the celiac plexus and delayed enhancement exceeding two-thirds of the tumor area on preoperative MDCT correlate with histologic evidence of perineural invasion in resected intrahepatic cholangiocarcinomas. MATERIALS AND METHODS: Two experienced abdominal radiologists retrospectively reviewed preoperative multiphasic MDCT scans of 20 patients who underwent resection of intrahepatic cholangiocarcinoma, identifying soft-tissue infiltration along the celiac plexus, delayed enhancement exceeding two-thirds of the tumor area, and maximum tumor diameter. Consensus findings were compared with intratumoral perineural invasion in resected intrahepatic cholangiocarcinomas using the Fisher exact test. RESULTS: Six patients had histologic intratumoral perineural invasion, five of whom had soft-tissue infiltration along the celiac plexus on preoperative MDCT, with corresponding 83.3% sensitivity and 92.9% specificity for perineural invasion and significant association between these MDCT and histologic findings (p = 0.002). No patients with histologic perineural invasion had enhancement exceeding two-thirds of the tumor area on MDCT; sensitivity was 0.0% for this finding. Tumor diameter on MDCT was not significantly associated with perineural invasion at histopathology (p = 0.530). CONCLUSION: Soft-tissue infiltration along the celiac plexus on MDCT is an indicator of perineural invasion in patients with intrahepatic cholangiocarcinoma. The data did not confirm an association between delayed enhancement exceeding two-thirds of the tumor area and perineural invasion. Because perineural invasion from intrahepatic cholangiocarcinoma is associated with a very poor prognosis and is generally a contraindication to surgery, the MDCT diagnosis of celiac plexus perineural invasion in patients with intrahepatic cholangiocarcinoma may have important implications for prognosis and treatment planning.

Idelalisib-associated Enterocolitis: Clinicopathologic Features and Distinction From Other Enterocolitides.

Idelalisib is a highly specific small-molecule phosphoinositide-3-kinase δ inhibitor that was recently approved by the Food and Drug Administration for the treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma and follicular lymphoma. The known side effects of idelalisib include severe diarrhea and colitis. Here we report the histologic findings in idelalisib-associated enterocolitis in 11 patients with chronic lymphocytic leukemia or follicular lymphoma receiving idelalisib over a 5-year period (2011 to 2015) at our institution. All 11 patients were receiving idelalisib and underwent colonoscopy for the evaluation of diarrhea. None of the patients had previously received a stem cell transplant. Histologically, the colon biopsies in all 11 cases showed some degree of apoptosis within crypts, with 5 cases showing moderate to severe apoptosis involving the majority of the crypts with loss of goblet cells. No viral inclusions were seen in any case and immunohistochemical stains for cytomegalovirus performed in 9/11 cases were negative. All cases showed at least focal acute cryptitis, and 8 of these cases showed mild architectural distortion. Increased inflammation within the lamina propria was seen in 7 cases, and increased intraepithelial lymphocytes within crypts was seen in 8 cases; the lymphocytes were mostly T cells with a predominance of CD8 T cells, with the majority expressing the α/ß T-cell receptor. Diagnoses of graft-versus-host disease, autoimmune enteropathy, infectious enterocolitis, and although thought to be less likely, inflammatory bowel disease were considered in each case. The presence of numerous intraepithelial lymphocytes in addition to severe villous blunting and apoptosis in the small intestinal biopsies from a subset of these patients additionally raised the possibility of autoimmune enteropathy, common variable immunodeficiency, or less likely, celiac disease. Awareness of the histologic features of idelalisib-associated enterocolitis is important to distinguish it from potential mimics, particularly graft-versus-host disease, autoimmune enteropathy, and cytomegalovirus/infectious enterocolitis.

Immunohistochemical panel for distinguishing esophageal adenocarcinoma from squamous cell carcinoma: a combination of p63, cytokeratin 5/6, MUC5AC, and anterior gradient homolog 2 allows optimal subtyping.

Distinguishing adenocarcinoma and squamous cell carcinoma of the esophagus is often based on morphological criteria and can be difficult in small biopsies. We analyzed commonly used immunohistochemical markers (p63, cytokeratin 5/6, cytokeratin 7, CDX2, MUC2, and MUC5AC) and 2 new markers, anterior gradient homolog 2 and SOX2, in esophageal carcinomas to establish the best panel to distinguish these tumors. Tissue microarrays with 69 esophageal adenocarcinomas and 41 whole sections of esophageal squamous cell carcinomas were stained for these markers and semiquantitatively scored. Sensitivities and specificities were calculated for individual markers and select combinations using the morphological diagnosis as a gold standard. All squamous cell carcinomas expressed p63 with 38 of 41 demonstrating reactivity in more than 75% of tumor cells. Cytokeratin 5/6 expression was seen in 40 of 41 squamous cell carcinomas with 39 of 41 demonstrating reactivity in more than 75% of tumor cells. SOX2 expression was present in 35 of 41 of squamous cell carcinomas but also in 24 of 69 of adenocarcinomas, frequently demonstrating extensive reactivity in adenocarcinomas. Anterior gradient homolog 2 was highly sensitive for adenocarcinoma and present in 68 of 69 of cases, but anterior gradient homolog 2 reactivity was also identified in 15 of 41 of squamous cell carcinomas, typically demonstrating focal reactivity in squamous cell carcinoma. MUC5AC expression was seen almost exclusively in adenocarcinomas with only a single squamous cell carcinoma demonstrating focal MUC5AC staining. Overall, the dual expression of both p63 and cytokeratin 5/6 was 99% specific and 98% sensitive for squamous cell carcinoma. In addition, anterior gradient homolog 2 and MUC5AC are useful positive markers of adenocarcinoma in the setting of absent or diminished p63 and cytokeratin 5/6 staining.

Clinicopathologic and molecular features of sporadic early-onset colorectal adenocarcinoma: an adenocarcinoma with frequent signet ring cell differentiation, rectal and sigmoid involvement, and adverse morphologic features.

Recent literature suggests an increasing incidence of colorectal carcinoma in young patients. We performed a histologic, molecular, and immunophenotypic analysis of patients with sporadic early-onset (≤40 years of age) colorectal carcinoma seen at our institution from the years 2000-2010 and compared these tumors to a cohort of consecutively resected colorectal carcinomas seen in patients >40 years of age. A total of 1160 primary colorectal adenocarcinomas were surgically resected for the years 2000 through 2010. Of these, 75 (6%) were diagnoses in patients ≤40 years of age of which 13 (17%) demonstrated abnormalities in DNA mismatch repair, 4 (5%) were in patients with known germline genetic disorders (two patients with familial adenomatous polyposis, one patient with juvenile polyposis, and one patient with Li-Fraumeni syndrome), and three patients (4%) had long-standing chronic inflammatory bowel disease. The sporadic early-onset colorectal carcinoma group comprised a total of 55 patients (55/1160, 5%) and were compared with a control group comprising 73 consecutively resected colorectal carcinomas with proficient DNA mismatch repair in patients >40 years of age. For the early-onset colorectal carcinoma group, most cases (33/55, 60%) were diagnosed between the age of 35 and 40 years of age. Compared with the control group, the early-onset colorectal carcinoma group was significantly different with respect to tumor location (P<0.007) with 80% (44/55 cases) identified in either the sigmoid colon (24/55, 44%) or rectum (20/55, 36%). Morphologically, early-onset colorectal carcinomas more frequently displayed adverse histologic features compared with the control colorectal carcinoma group such as signet ring cell differentiation (7/55, 13% vs 1/73, 1%, P=0.021), perineural invasion (16/55, 29% vs 8/73, 11%, P=0.009) and venous invasion (12/55, 22% vs 4/73, 6%, P=0.006). A precursor adenomatous lesion was less frequently identified in the early-onset colorectal carcinoma group compared with the control group (19/55, 35% vs 39/73, 53%, P=0.034). Of the early-onset colorectal carcinomas, only 2/45 cases (4%) demonstrated KRAS mutations compared with 11/73 (15%) of the control group colorectal adenocarcinomas harboring KRAS mutations, although this difference did not reach statistical significance (P=0.13). BRAF V600E mutations were not identified in the early-onset colorectal carcinoma group. No difference was identified between the two groups with regard to tumor stage, tumor size, number of lymph node metastases, lymphatic invasion, tumor budding, mucinous histology, or tumor-infiltrating lymphocytes. Both groups had similar recurrence-free (P=0.28) and overall survival (P=0.73). However, patients in the early-onset colorectal carcinoma group more frequently either presented with or developed metastatic disease during their disease course compared with the control colorectal carcinoma group (25/55, 45% vs 18/73, 25%, P=0.014). In addition, 8/55 patients (15%) in the early-onset colorectal carcinoma group developed local recurrence of their tumor while no patients in the control colorectal carcinoma group developed local recurrence (P<0.001), likely due to the increased incidence of rectal carcinoma in the patients with early-onset colorectal carcinoma. Our study demonstrates that colorectal carcinoma is not infrequently diagnosed in patients ≤40 years of age and is not frequently the result of underlying Lynch syndrome or associated with other cancer-predisposing genetic conditions or chronic inflammatory conditions. These tumors have a striking predilection for the distal colon, particularly the sigmoid colon and rectum and are much more likely to demonstrate adverse histologic factors, including signet ring cell differentiation, venous invasion, and perineural invasion.

Myometrial xanthomatosis: possible relationship to prior pregnancy procedure.

We report 3 unique cases of extensive myometrial infiltration by foamy histiocytes in uteri removed for benign conditions. The histologic findings were similar and consisted of diffuse infiltration of myometrium by clusters, cords, and sheets of CD163-positive histiocytes with no other significant inflammatory cell component. Most of the histiocytes had pale, vacuolated, or foamy cytoplasm, but in 1 case eosinophilic granular cytoplasm was also present. In all cases, the nuclei were small and eccentric. No mitotic figures were identified. All cases involved young, parous women who had remote prior surgical interventions involving the uterus; 2 patients had a prior cesarean section and 1 had a prior therapeutic abortion. There was no associated neoplastic or infectious condition in any of the cases, and no patient had a prior history of pelvic inflammatory disease. Although we were unable to obtain more detailed obstetric history, an exuberant and persistent reaction to the surgical procedure and/or to a carrier substance for uterotonic intramyometrial injection may be the basis for this unusual reaction, which we designate as myometrial xanthomatosis.

The small organic compound HMN-176 delays satisfaction of the spindle assembly checkpoint by inhibiting centrosome-dependent microtubule nucleation.

HMN-176 is a potential new cancer therapeutic known to retard the proliferation of tumor cell lines. Here, we show that this compound inhibits meiotic spindle assembly in surf clam oocytes and delays satisfaction of the spindle assembly checkpoint in human somatic cells by inducing the formation of short and/or multipolar spindles. HMN-176 does not affect centrosome assembly, nuclear envelope breakdown, or other aspects of meiotic or mitotic progression, nor does it affect the kinetics of Spisula or mammalian microtubule (MT) assembly in vitro. Notably, HMN-176 inhibits the formation of centrosome-nucleated MTs (i.e., asters) in Spisula oocytes and oocyte extracts, as well as from isolated Spisula or mammalian centrosomes in vitro. Together, these results reveal that HMN-176 is a first-in-class anticentrosome drug that inhibits proliferation, at least in part, by disrupting centrosome-mediated MT assembly during mitosis.