Toshihiro Haga

Retinoic acid-inducible gene-I is constitutively expressed and involved in IFN-γ-stimulated CXCL9-11 production in intestinal epithelial cells

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH/D family proteins, and plays an important role in antiviral response via interferon-stimulated genes (ISGs) and type 1 IFN. In this study, the roles of RIG-I in the epithelial cells in the cross-talk between type 2 IFN and inducible chemokines production are high-lighted. The results showed that RIG-I was constitutively expressed in normal surface epithelia lining the colonic mucosa. RIG-I was constitutively expressed in the epithelial cell lines HT-29, and IFN-gamma and TNF-alpha enhanced the RIG-I expression in a dose-dependent manner. IFN-gamma was shown to stimulate CXCL9-11 production, and RNA interference against RIG-I resulted in significant decrease of IFN-gamma-induced CXCL9-11 productions. These results suggest that RIG-I play an important role in the cross-talk between inflammatory cytokines and immune cell trafficking. In conclusion, RIG-I might regulate the gut barrier function in homeostatic and inflammatory conditions.

Invasive micropapillary carcinoma of the extrahepatic bile duct and its malignant potential

Invasive micropapillary carcinoma (IMPC) was originally described as a distinctive type of invasive carcinoma in the breast, but it has not been recognized as a histological type of the extrahepatic bile duct cancer. The present study demonstrated clinicopathological features and patient prognosis of IMPC. We examined histological reviews of 93 consecutive cases of the extrahepatic bile duct cancer and identified 13 cases which included IMPC component. The component of IMPC ranged from 5 to 60% of the primary tumor tissue, which was mainly detected at the invasive front of the tumor. Of the 13 cases, 12 (92.3%) carcinomas with IMPC showed lymph node metastasis more frequently compared to conventional adenocarcinoma (39.2%, P<0.001). Presence of IMPC component was significantly associated with poor overall survival (P=0.003). In conclusion, extrahepatic bile duct carcinoma with IMPC component showed significant lymphatic invasion, lymph node metastasis, and resulted in poor prognosis.

Pathological characteristics of early to advanced gallbladder carcinoma and extrahepatic cholangiocarcinoma

Biliary tract cancer (cancer of gallbladder and extrahepatic bile duct) is the most common malignancy of the biliary tract, and is considered to be a high‐grade malignancy. In this study, we reviewed 293 gallbladder cancers and 102 bile duct cancers for clarifying growth and invasion of the extrahepatic bile duct cancer. Only 10.5% (9/86) of the early gallbladder cancers showed lymphatic invasion, but neither venous invasion nor lymph node metastasis was noted in the early cancers. 70.6% (207/293) of the gallbladder cases were pT2‐3 cancers, and frequently showed lymphatic/venous/perineural invasion and/or lymph node metastasis. 12.7% (13/102) of the extrahepatic bile duct cancers were pTis or pT1 cancers, which were categorized as early cancers. Only 15.4% (2/13) of the early cancer showed vascular/perineural invasion and/or lymph node metastasis. The majority (87.3%) of the extrahepatic bile duct cases was pT2‐3 cancers, and frequently showed vascular/perineural invasion and/or lymph node metastasis. We also examined intramural invasion patterns; i.e. intramural invasion patterns were defined as infiltrative growth (IG) type, and destructive growth (DG) type. The overall survival rate of the gallbladder cancer patients with the DG type was significantly lower than that of the patients with the IG type, associated with frequent lymphatic/venous invasion and/or lymph node metastasis. Therefore, pathological characteristics are important for clinical manifestation of the gallbladder/extrahepatic bile duct cancers.

Expression of cancer-associated fibroblast markers in advanced colorectal cancer

Colorectal cancer is one of the most common causes of mortality from cancer worldwide. Previous studies have demonstrated that cancer-associated fibroblasts (CAFs) promote neoangiogenesis and tumor growth for various tumors. The present study analyzed CAF markers, including α-smooth muscle actin (α-SMA), collagen I, platelet-derived growth factor receptor-β (PDGFR-β), and D2-40 (antibody recognizing podoplanin), and vessel markers, including cluster of differentiation (CD)31 and CD34, for 121 advanced colorectal cancer cases using a digital image analyzing technique. The association between CAF markers and vessel markers with clinicopathological factors was investigated. Furthermore, the association between CAF markers with each other, and their association with vessel markers was analyzed. Mean/median expression area of stromal and vessel markers in tumors were collagen I, 26.787%; D2-40, 1.372%; PDGFR-β, 11.646%; α-SMA-positive and desmin-negative myofibroblasts (α-SMA subtraction), 15.372%; CD31, 3.635%; and CD34, 2.226%. The expression area of α-SMA subtraction was significantly correlated with collagen I (P<0.001, correlation rho=0.509). High levels of α-SMA subtraction (P=0.002), collagen I (P=0.040), and PDGFR-β (P=0.040) expressions tended to be associated with high venous invasion. D2-40 did not correlate with other CAF and vessel markers. These results indicated that individual CAFs may have different expression patterns, and different strength effects for venous invasion in advanced colorectal cancer stroma.

Development of Hepatocellular Carcinoma in Chronic Hepatitis C Patients 20 Years after Achieving a Sustained Virological Response with Interferon Therapy: A Report of Two Cases

Advances in interferon (IFN)‐based therapy for chronic hepatitis C have led to a high rate of sustained virological response (SVR), which means viral clearance. However, some cases have been reported to develop hepatocellular carcinoma (HCC) over 10 years after achieving the SVR. Here, we report two patients who developed HCC 20 years after SVR with IFN therapy. Both of the patients were male and achieved SVR at the age of 46 years and 61 years, respectively. These cases suggest the need for long‐term follow‐up in patients with chronic hepatitis C even if SVR is achieved.

Neoangiogenesis of gastric submucosa‑invasive adenocarcinoma

Early gastric cancer may be defined as mucosal or submucosal invasive carcinoma, and exhibits a good prognosis: 90% of patients survive >10 years. Early gastric cancer infrequently exhibits lymph node metastasis, although submucosal invasion, the presence of vascular invasion and/or lymphatic permeation are independent risk factors for lymph node metastasis in early gastric cancer. The analysis of tumor lymphangiogenesis and angiogenesis are important to determine the extent of invasive progression and metastasis in patients. Previously, the presence of vessels expressing the D2-40 antibody and the factor-VIII protein has been identified immunohistochemically. The vessels that are immunoreactive for D2-40 and factor-VIII are morphologically similar to lymphatic vessels or small-size veins, also termed venules. In the present study, the association between tumor invasion and neoangiogenesis in early gastric cancer was examined. The D2-40/factor-VIII double-stained vessel (DSV) density was analyzed, in addition to lymphatic and blood vessel (vein and artery) density, using 46 submucosa-invasive and 50 mucosal carcinomas, and 20 non-neoplastic gastric tissues. The lymphatic density and DSV density of submucosa beneath the carcinoma and submucosa of the surrounding region in submucosa-invasive carcinoma were significantly increased (P<0.001) in comparison with those in mucosal carcinoma or non-neoplastic gastric tissue. No significant difference was observed in blood vessel density between non-neoplastic gastric, mucosal carcinoma and submucosa-invasive carcinoma tissues other than that of mucosa. The present study suggests the potential for the presence of D2-40/factor-VIII DSV and the importance of this vessel for neoangiogenesis in early gastric cancer.

Correlation between DEC1/DEC2 and epithelial‑mesenchymal transition in human prostate cancer PC‑3 cells

Differentiated embryonic chondrocyte (DEC) genes have been reported to be involved in the regulation of mammalian circadian rhythms, differentiation, apoptosis, the response to hypoxia and epithelial-mesenchymal transition (EMT). Activation of transforming growth factor (TGF)-β signaling is known to promote EMT for the development of metastatic castration-resistant prostate cancer (PCa). However, the role of DEC genes in the TGF-β-induced EMT of PCa remains unclear. In the present study it was demonstrated that TGF-β increased the transcriptional/translational levels of DEC1 but decreased those of DEC2 in PC-3 cells. Moreover, TGF-β evoked the phosphorylation of Smad2, followed by the activation of mesenchymal markers, such as N-cadherin and vimentin, in addition to the suppression of epithelial markers, such as E-cadherin. The knockdown of DEC1 restrained TGF-β-induced cell morphology changes as well as cell motility, which was compatible with the upregulation of E-cadherin and downregulation of pSmad2, N-cadherin, and vimentin. However, DEC2 knockdown endorsed PC-3 cells with a more metastatic phenotype. EMT-related markers in DEC2 siRNA-transfected cells exhibited a reverse expression pattern when compared with that in DEC1 siRNA-transfected cells. Taken together, these results provide evidence that DEC1 and DEC2 have opposite effects on TGF-β-induced EMT in human prostate cancer PC-3 cells.

A new histological therapeutic classification system to predict eradicated and residual lymph nodes in breast cancer after neoadjuvant chemotherapy

The indication for neoadjuvant chemotherapy (NAC) has recently broadened to include its use in the treatment of initial stage breast cancer. Axillary lymph node metastasis after NAC in breast cancer is a poor prognostic factor. Thus, the prediction of lymph node metastasis is important to estimate the prognosis of breast cancer patients after NAC. Therefore, we focused on residual carcinoma patterns of primary breast tumors after NAC and examined the correlation between the patterns and lymph node metastasis. In this study, we examined 50 breast cancer specimens and associated dissected lymph nodes after NAC. We divided 40 cases into an eradicated lymph node group and a residual lymph node group to analyze residual carcinoma patterns of primary breast tumors. Residual carcinoma patterns were classified according to the cell density of carcinoma cells: dense, focal/nested and sporadic/in-situ. There were significant differences in residual carcinoma patterns (P<0.01) among the three pattern groups. There was a high incidence of dense patterns in the residual lymph node group and a high incidence of sporadic/in-situ patterns in the eradicated lymph node group. Analysis of residual carcinoma patterns of primary breast tumors and clinicopathological factors demonstrated that there were significant differences in tumor reduced ratio on CT (P<0.001), primary tumor area before NAC (P<0.01), primary tumor area after NAC (P<0.00001), intrinsic subtype (P<0.01), Ki-67 labeling index (P<0.01), histological grade (P<0.05) and mitotic count (P<0.01) between the dense and non-dense groups. Therefore, our results suggest that the residual carcinoma pattern is useful for predicting eradicated or residual lymph nodes and the malignant potential in breast cancer after NAC.

Myofibroblasts of the muscle layer stimulate the malignant potential of colorectal cancer

Myofibroblasts of colorectal cancer (CRC) have been associated with histopathological factors such as lymph node metastasis, liver metastasis and local recurrence. However, few studies have assessed the association between these malignant potentials and the myofibroblast distribution in CRC. We aimed to evaluate the relationship between clinical factors and myofibroblast distribution around CRC invasive lesions. The study included 121 cases of pT3 CRC that were diagnosed at stage II or III. Myofibroblast density of the following three histological layers was measured: the submucosa (SM), muscularis propria (MP) and subserosa (SS). We analyzed the relationship between the clinicopathological factors and myofibroblast density by studying the histopathological features of the three layers. The myofibroblast density of the MP layer was significantly higher in the groups with high-frequency lymphatic and venous invasion than the groups with low-frequency lymphatic (P<0.001) and venous (P<0.01) invasion, respectively. In the positive lymph node metastasis group, the myofibroblast density at the MP layer was significantly higher than that in the negative lymph node metastasis group (P<0.001). The high myofibroblast density group at the MP layer was significantly associated with poor overall survival (P<0.003). Our study indicated that myofibroblasts are a type of cancer-associated fibroblasts and that the myofibroblast distribution contributes to the malignant potential of CRC. Furthermore, we demonstrated that myofibroblasts present at the MP layer play an important role in the malignant potential and poor prognosis of patients with CRC.

Myofibroblast distribution is associated with invasive growth types of colorectal cancer

Both the invasive growth types of colorectal cancer (CRC) and the number of myofibroblasts have been associated with histopathological factors such as lymph node and liver metastasis, and local recurrence. However, there are few studies, that have assessed the association between invasive growth type and myofibroblast distribution in CRC. We aimed to evaluate the relationship between the clinicopathological factors of CRC and two invasive growth types, the expanding and infiltrating types. We categorized 150 cases of pT3 CRC into the expanding and infiltrating types and measured the myofibroblast density of three histological layers: the submucosa (SM), the muscularis propria (MP) and the subserosa (SS). We compared these two invasive growth types and analyzed the relationship between clinicopathological factors and myofibroblast density. Myofibroblast density was significantly higher in the infiltrating type than that in the expanding type (P<0.05). In the lymph node metastasis-positive group of the infiltrating type, myofibroblast density in MP was significantly higher than that in the lymph node metastasis-negative group (P<0.001). In the infiltrating type, the group with the higher level of lymphatic invasion had a significantly higher density of myofibroblasts in the MP than the group with the lower level of lymphatic invasion (P<0.01). These results suggest that myofibroblasts participate more in the infiltrating type compared with the expanding type of CRC. It would appear that myofibroblasts present in the MP play an important role in the malignant potential of the infiltrating type compared to the expanding type.