Richard Kirsch

Cancer-Associated Fibroblasts Drive the Progression of Metastasis through both Paracrine and Mechanical Pressure on Cancer Tissue

Neoplastic cells recruit fibroblasts through various growth factors and cytokines. These “cancer-associated fibroblasts” (CAF) actively interact with neoplastic cells and form a myofibroblastic microenvironment that promotes cancer growth and survival and supports malignancy. Several products of their paracrine signaling repertoire have been recognized as tumor growth and metastasis regulators. However, tumor-promoting cell signaling is not the only reason that makes CAFs key components of the “tumor microenvironment,” as CAFs affect both the architecture and growth mechanics of the developing tumor. CAFs participate in the remodeling of peritumoral stroma, which is a prerequisite of neoplastic cell invasion, expansion, and metastasis. CAFs are not present peritumorally as individual cells but they act orchestrated to fully deploy a desmoplastic program, characterized by “syncytial” (or collective) configuration and altered cell adhesion properties. Such myofibroblastic cohorts are reminiscent of those encountered in wound-healing processes. The view of “cancer as a wound that does not heal” led to useful comparisons between wound healing and tumorigenesis and expanded our knowledge of the role of CAF cohorts in cancer. In this integrative model of cancer invasion and metastasis, we propose that the CAF-supported microenvironment has a dual tumor-promoting role. Not only does it provide essential signals for cancer cell dedifferentiation, proliferation, and survival but it also facilitates cancer cell local invasion and metastatic phenomena. Mol Cancer Res; 10(11); 1403–18. ©2012 AACR.

Activated mucosal mast cells differentiate eosinophilic (allergic) esophagitis from gastroesophageal reflux disease.

Objectives: To evaluate the utility of activated mucosal mast cells (MC) in the differential diagnosis of eosinophilic esophagitis (EE) and gastroesophageal reflux disease (GERD). Methods: Intraepithelial eosinophils and MC were quantified in esophageal biopsies from 25 children with EE, 22 children with GERD and 22 controls. MCs were identified by immunohistochemistry for MC tryptase, whereas MC activation status was evaluated by immunohistochemistry for immunoglobulin E (IgE) and by electron microscopy. Results: Esophageal biopsies from patients with EE showed higher intraepithelial eosinophil counts (55 ± 27.5 vs 6.9 ± 9.7, P < 0.0001) and MC counts (26.3 ± 12.7 vs 7.8 ± 8.9, P < 0.0001) than those from patients with GERD. Almost all EE biopsies (24 of 25 patients; 96%) contained IgE-bearing cells compared with 9 of 22 (41%) GERD biopsies (P < 0.001). GERD biopsies with intraepithelial eosinophil counts >7/high-power field (suggesting an allergic component) contained IgE-bearing cells in 6 of 7 (86%) cases compared to 3 of 15 (20%) cases with eosinophil counts <7/h.p.f (P < 0.01). No intraepithelial eosinophils, MC or IgE-positive cells were present in controls. Electron microscopy confirmed the presence of intraepithelial MC and changes in cytoplasmic granules indicative of MC and eosinophil activation. Conclusions: Intraepithelial MC counts and IgE-bearing cells may help to differentiate EE and GERD and to define a subset of GERD patients in which an allergic component is present. The findings support a role for a MC-mediated hypersensitivity reaction in the pathogenesis of EE.

Collective migration of cancer-associated fibroblasts is enhanced by overexpression of tight junction-associated proteins claudin-11 and occludin

It has been suggested that cancer‐associated fibroblasts (CAFs) positioned at the desmoplastic areas of various types of cancer are capable of executing a migratory program, characterized by accelerated motility and collective configuration. Since CAFs are reprogrammed derivatives of normal progenitors, including quiescent fibroblasts, we hypothesized that such migratory program could be context‐dependent, thus being regulated by specific paracrine signals from the adjacent cancer population. Using the traditional scratch assay setup, we showed that only specific colon cancer cell lines (i.e. HT29) were able to induce collective CAF migration. By performing quantitative proteomics (SILAC), we identified a 2.7‐fold increase of claudin‐11, a member of the tight junction apparatus, in CAFs that exerted such collectivity in their migratory pattern. Further proteomic investigations of cancer cell line secretomes revealed a specific signature, involving TGF‐β, as potential mediator of this effect. Normal colonic fibroblasts stimulated with TGF‐β exerted myofibroblastic differentiation, occludin (OCLN) and claudin‐11 (CLDN11) overexpression and cohort formation. Subsequently, inhibition of TGF‐β attenuated all the previous effects. Immunohistochemistry of the universal tight junction marker occludin in a cohort of 30 colorectal adenocarcinoma patients defined a CAF subpopulation expressing tight junctions. Overall, these data suggest that cancer cells may induce CLDN11 overexpression and subsequent collective migration of peritumoral CAFs via TGF‐β secretion.

Clinicopathologic spectrum of massive and submassive hepatic necrosis in infants and children

Clinicopathologic features of 45 patients with fulminant hepatic failure due to massive or submassive hepatic necrosis were studied. Both percutaneous biopsies and liver explants were available in 23 patients, whole livers only in 11 cases, and biopsies only in 11 cases. An etiologic diagnosis was established in 16 cases (36%). A further 3 cases (7%) were associated with aplastic anemia. Established etiologies included drug reactions (n = 7); autoimmune hepatitis, type 2 (n = 3); halothane hepatitis (n = 1); ischemia/hypotension (n = 1); mushroom poisoning (n = 1); mitochondrial disorder (n = 1); hemophagocytic lymphohistiocytosis (n = 1); and adenoviral hepatitis (n = 1). The extent of necrosis on liver biopsy correlated poorly with that in liver explants (mean difference, 32% +/- 23.8%). Almost all cases could be classified into one of 2 broad patterns of necrosis, namely, (1) zonal coagulative necrosis or (2) panlobular (nonzonal) necrosis. These patterns differed significantly with respect to several clinical parameters including sex ratio, peripheral blood white cell count, serum aspartate transaminase and alanine transaminase, conjugated bilirubin, and alkaline phosphatase levels. Livers with panlobular necrosis showed a spectrum of histopathologic findings that included central venulitis (76%), lymphocytic infiltration of large duct/gallbladder epithelium (54%), and syncytial giant cell transformation (18%). These features were not seen in livers with zonal coagulative necrosis which frequently showed prominent steatosis (91%). Both patterns of necrosis frequently showed ductular proliferation (100%) and cholangiolitis (80%). The diagnostic yield of ancillary studies (histochemistry, immunohistochemistry, and electron microscopy) was very low (<1%). The small proportion of cases with etiologic diagnoses precluded correlation of clinical and histopathological parameters with specific etiologies. In summary, this study describes the spectrum of changes seen in massive and submassive necrosis in children and identifies clinical features that might differentiate between 2 broad patterns of necrosis.

Distinctive histopathologic phenotype in resection specimens from patients with Crohn's disease receiving anti-TNF-α therapy.

Anti-tumor necrosis factor α (anti-TNF-α) therapy can result in endoscopic healing, reduction of symptoms, and reduced need for surgery and hospitalization in many patients with Crohns disease (CD). Earlier data suggested that anti-TNF-α therapy may be associated with fibrosis and stricturing. We sought to determine whether anti-TNF-α therapy affects histologic inflammation, fibrosis, and granuloma formation. Hematoxylin and eosin sections from 62 patients with CD treated with either infliximab or adalimumab and 80 controls undergoing the same surgery but without prior exposure to anti-TNF-α therapy were compared. All patients with CD had undergone surgery within 6 months of therapy; CD controls were matched for steroid exposure, procedure, and indication for surgery and were subcategorized and case matched. Blinded histologic assessment of all slides was performed using a semiquantitative scoring system to assess inflammatory changes and fibrosis in all bowel layers. Compared with controls, the group treated with anti-TNF-α showed a reduction in mucosal and submucosal inflammation (P < .05), a decrease in granuloma formation (P < .05), and an increase in duplication of the muscularis mucosae (P < .05). A notable feature was a distinct pattern of hyalinizing submucosal fibrosis that was often devoid of inflammatory cells and that started directly below the muscularis mucosae; this pattern was not observed in the control group (P < .05). Resection specimens from patients with CD treated with anti-TNF-α therapy showed (a) reduced mucosal and submucosal inflammation; (b) a decrease in granuloma formation; and (c) a distinct pattern of submucosal hyaline fibrosis, with increased fibrosis in the muscularis mucosae and muscularis propria.

Ileal Pouch Symptoms Do Not Correlate With Inflammation of the Pouch

BACKGROUND & AIMSnPouchitis is the most common complication after ileal pouch-anal anastomosis (IPAA). However, symptoms are not specific. The Pouchitis Disease Activity Index (PDAI) and the Pouchitis Activity Score (PAS) have been used to diagnose pouchitis. We evaluated the correlation between the clinical components of these scores and endoscopic and histologic findings.nnnMETHODSnWe performed a cross-sectional study, analyzing data from 278 patients from Mount Sinai Hospital (Toronto, Canada) who had an IPAA. Patients underwent pouchoscopy with a biopsy, and data were collected on patients clinical status. The PDAI and PAS were calculated for each subject. The Spearman rank correlation (ρ) statistical test was used to evaluate correlations between the PDAI scores and PAS, and between total scores and subscores.nnnRESULTSnThe total PDAI scores and PAS scores were correlated; the clinical components of each correlated with the total score (ρ = 0.59 and ρ = 0.71, respectively). However, we observed a low level of correlation between clinical and endoscopic or histologic subscores, with ρ of 0.20 and 0.10, respectively, by PDAI, and ρ of 0.19 and 0.04, respectively, by PAS.nnnCONCLUSIONSnThere is a low level of correlation between clinical and endoscopic and histologic subscores of patients with IPAA; clinical symptoms therefore might not reflect objective evidence of inflammation. These findings, along with evidence of correlation between total scores and clinical symptoms, indicate that these indices do not accurately identify patients with pouch inflammation. Further research is required to understand additional factors that contribute to clinical symptoms in the absence of objective signs of pouch inflammation.

Ileal “carcinoid” tumors—small size belies deadly intent: high rate of nodal metastasis in tumors ≤1 cm in size

Neuroendocrine tumors (NETs) account for 2% of tumors of the gastrointestinal tract, most occurring in the small intestine. A size of 2 cm is generally regarded as a cut-off point for risk of lymph node metastasis in intestinal neuroendocrine tumors in the absence of other high-risk features; however, metastatic disease has been reported in 12% of tumors of the jejunum and ileum measuring 1 cm or less. Archives from 2 institutions were searched for ileal NETs measuring 1 cm or less, and selected data were recorded. Twenty-one ileal NETs were identified measuring ≤1 cm. Six (29%) were multifocal and 7 (33%) had distant metastasis at diagnosis. Regional lymph nodes were examined in 14 cases (67%), and 10 of these cases (71%) showed lymph node metastasis. Mean primary tumor size in cases with nodal metastasis was 7.3 mm. In this series of ileal NETs ≤1 cm in size, the rate of lymph node metastasis was 48% overall and 71% for cases with regional lymph node resections. In addition, 33% showed distant metastasis at the time of diagnosis. Tumors as small as 3 mm and those confined to the submucosa can give rise to nodal metastasis, emphasizing the need for consideration of local resection with regional lymphadenectomy, even for subcentimeter ileal NETs.

Intraepithelial lymphocytosis is a frequent finding in biopsies from ileal pouch–anal anastomoses

Following restorative proctocolectomy with an ileal pouch-anal anastomosis, the small bowel mucosa undergoes several specific histologic adaptions, which may be unrelated to the underlying disease or symptoms of pouchitis. An increase in intraepithelial lymphocytes (IELs) has not been described as part of this spectrum. Mucosal biopsies of the ileal pouch and afferent limb of 230 patients (mean age: 45.7y [18.3-74.7], gender [female/male]: 117/113) with a functioning ileal pouch-anal anastomosis (mean time since ileostomy closure: 10.8months) and associated clinically annotated outcome data were assessed for IELs/100 enterocytes. Forty-two patients (18.3%) showed an increase in IELs (≥20 IELs/100 enterocytes [range 20-39]), in pouch and/or afferent limb biopsies. Intraepithelial lymphocytosis was more commonly observed in afferent limb compared to pouch biopsies (18.8% vs 8.3%; P = .42) and in familial adenomatous polyposis compared to ulcerative colitis patients (16% vs 8%; P = 0.36), but neither difference reached statistical significance. No cases with increased IELs displayed severe villous blunting. Increased IELs were not significantly associated with age, sex, ethnicity, smoking history, time since ileostomy, use of antibiotics, biologic agents, anti-diarrheal agents or probiotics, C-reactive protein levels or differential white cell count. None of the 42 patients with increased IELs had positive celiac serology (anti-human tissue transglutaminase IgA [ELISA] with corresponding total serum IgA). Intraepithelial lymphocytosis in pouch biopsies may represent a subclinical response to an altered bacterial microenvironment. Pathologists should be aware that intraepithelial lymphocytosis is part of the spectrum of changes in pouch biopsies, and only rarely is due to celiac disease.

Familial PDGFRA mutation- syndrome: somatic and gastrointestinal phenotype.

Germline activating platelet-derived growth factor receptor alpha (PDGFRA) mutations have been described in four families. All the index patients have presented with multiple mesenchymal tumors of the gastrointestinal tract. We identified a fifth family with four first-degree relatives that harbor a PDGFRA exon 18 (D846V) germline mutation. The affected kindred have a unique phenotype including coarse facies and skin, broad hands and feet, and previously undescribed premature tooth loss. While the index patient presented with multiple small bowel inflammatory fibroid polyps (IFPs) and has a gastric gastrointestinal stromal tumor (GIST), no tumors have yet been identified in other family members. We describe the pathology, genetics, the incomplete penetrance and variable expressivity of the familial PDGFRA-mutation syndrome referencing the mouse knock-in Pdgfra model. We speculate on the role of the telocyte, a recently described CD34, PDGFRA+ stromal cell, in the development of inflammatory fibroid polyps and the somatic phenotype.