Mitsumasa Osakabe

Tumor budding at the invasive front of colorectal cancer may not be associated with the epithelial-mesenchymal transition

Tumor budding is thought to reflect the epithelial-mesenchymal transition (EMT). However, the molecular mechanism linking tumor buds and the EMT remains unclear. Here, we examined the induction of tumor budding and EMT and their association with EMT-related proteins (ZEB1, TWIST, SNAIL, and SLUG) in colorectal cancer (CRC). Immunohistochemical expression of pan-cytokeratin was examined for identification of tumor budding in 101 CRCs. Grading of tumor budding was classified into low- and high-grade groups. Tissue microarray was conducted to identify tumor budding sites. The expression of E-cadherin, ZEB1, TWIST, SNAIL, and SLUG was examined in areas of tumor budding and the surrounding tumor stroma using a double-immunostaining method. Specifically, pan-cytokeratin and EMT-related proteins were assessed by double immunostaining. Low or no expression of E-cadherin was found in areas of tumor budding. Moreover, ZEB1, TWIST, SNAIL, and SLUG were not expressed in regions of tumor budding. However, the expression level of ZEB1 in the stromal cells surrounding tumor budding was significantly more frequent than that of TWIST, SNAI, and SLUG. In addition, the expression of EMT-related proteins in surrounding stromal cells was significantly greater in areas of high-grade tumor budding than in low-grade areas. Our present results suggest that EMT-related proteins play a minor role in forming tumor buds. In addition, our findings suggest the existence of subtypes of stromal cells in CRC with phenotypical and functional heterogeneity.

Vascular Invasion and Stromal S100A4 Expression at the Invasive Front of Colorectal Cancer are Novel Determinants and Tumor Prognostic Markers

Object: The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors associated with sporadic colorectal cancer (CRC). We examined the clinicopathological findings and immunohistochemical expression of tumor prognostic markers at tumor budding sites to determine their predictive value for patient prognosis. Materials and Methods: Immunohistochemical examination was performed by tissue microarray (TMA) of specimens from 106 patients with CRC. On hematoxylin and eosin (H&E)-stained tumor tissue slides, a representative area of tumor budding at the invasive front was selected for the construction of a TMA. Immunostaining for matrix metalloproteinase-7 (MMP7), the laminin-5 (ln-5) γ2 chain and S100A4 was performed to determine the association between patient survival and these markers. Results: Clinicopathological variables were also assessed. Tumor location, histological type, degree of lymphatic invasion and vascular invasion, tumor stage, epithelial expression of S100A4, stromal cell expression of S100A4 and expression of the ln-5γ2 chain were associated with an increased risk of mortality. Five factors were retained in the multivariate logistic regression analysis. Specifically, the tumor location, degree of lymphatic invasion and vascular invasion, tumor stage and stromal cell expression of S100A4 remained significant predictors of patient survival after controlling for the other variables. Conclusion: Vascular invasion and stromal expression of S100A4 in the tumor budding areas correlated with patient survival. Stromal immunostaining of S100A4 may be useful for identifying high-risk patients with advanced CRC.

Primary Central Nervous System Lymphoma Presenting as Growing Intracerebral Hemorrhage

BACKGROUND Hemorrhage at presentation in primary central nervous system (CNS) lymphoma is rare. We encountered a case of primary CNS lymphoma presenting as a growing intracerebral hemorrhage. CASE DESCRIPTION An 80-year-old man presented with mild dysarthria. Computed tomography demonstrated a round, high-density mass with surrounding vasogenic edema in the left frontal lobe. Although the patient was placed on antihypertensive therapy for suspected subacute subcortical hemorrhage, neurologic symptoms gradually worsened. Computed tomography after 2 weeks revealed that the high-density lesion and surrounding edema had increased in size compared with previous images. The patient had been transferred to our hospital 14 days after admission to another institution. Magnetic resonance imaging demonstrated a mass lesion comprising hemorrhage of different phases in the left frontal lobe. Contrast-enhanced T1-weighted imaging demonstrated a mass lesion with heterogeneous enhancement in the left frontal lobe. The patient underwent craniotomy with gross total removal of the hemorrhagic lesion. The histopathologic diagnosis was diffuse large-cell non-Hodgkin lymphoma, and immunohistochemistry showed high immunoreactivity for vascular endothelial growth factor. CONCLUSION Although exceedingly rare, primary central nervous system lymphoma can present as growing intracerebral hemorrhage due to repeated intratumoral hemorrhages. High expression of vascular endothelial growth factor and the mass effects of hemorrhage could be associated with the onset and growth of intracerebral hemorrhage. Early evaluation and meticulous observation are important to avoid progressive, life-threatening situations in such cases.

Protein expression patterns in cancer-associated fibroblasts and cells undergoing the epithelial-mesenchymal transition in ovarian cancers

Recent studies have shown that cancer-associated fibroblasts (CAFs) and the epithelial-mesenchymal transition (EMT) contribute to invasive and metastatic abilities of ovarian cancer (OC) cells. In the present study, we attempted to identify the role of CAF- and EMT-related proteins in OCs, including serous carcinoma, mucinous carcinoma, endometrioid carcinoma and clear cell carcinoma using an immunohistochemical approach. The following CAF-related markers were used: CD10, podoplanin, fibroblast activating protein (FAP), platelet derived growth factor receptor (PDGFRα), PDGFRβ, S100A4 and α-smooth muscle actin (α-SMA). In addition, the following EMT-related markers were investigated: Slug, TWIST1 and ZEB1We performed hierarchical cluster analysis to group the samples according to their scoring. Subgroup 1 was characterized by high expression of CD10, podoplanin, α-SMA, Slug and ZEB1, whereas subgroup 2 was closely associated with high expression of podoplanin, PDGFRα, PDGFRβ, α-SMA, and Slug. In addition, marked expression of CD10 was observed in subgroup 3. High expression of α-SMA was a distinctive feature in subgroup 4, and expression of podoplanin and α-SMA characterized subgroup 5. Each subgroup was correlated with a histological type. The fact that different histological types were associated with different subgroups suggests the presence of distinct and heterogeneous subpopulations of CAFs in OC.

Analysis of the expression of cancer-associated fibroblast- and EMT-related proteins in submucosal invasive colorectal cancer

Objective: Recent studies have shown that cancer-associated fibroblasts (CAFs) and the epithelial-mesenchymal transition (EMT) play important roles in the progression and metastasis of CRC. Although prediction of lymph node metastasis in submucosal invasive colorectal cancer (SiCRC) is important, the relationships of CAF and EMT with lymph node metastasis of SiCRC have not yet been examined. Here, we aimed to analyze the expression patterns of CAF- and EMT-related proteins in SiCRC. Materials and Methods: The expression of CAF-related markers, including α-smooth muscle actin, CD10, podoplanin, fibroblast specific protein 1, and adipocyte enhancer-binding protein 1, and EMT-related proteins [zinc finger protein SNAI2 (ZEB1) and twist-related protein 1 (TWIST1) in SiCRC with (n = 29) or without (n = 80) lymph node metastasis was examined by immunohistochemistry. We examined the expression patterns of biomarkers using hierarchical cluster analysis. Consequently, four subgroups were established based on the expression patterns of CAF- and EMT-related markers, and the associations of these subgroups with clinicopathological variables. Results: In multivariate analysis, subgroup 2, which was characterized by high expression of all markers, was correlated with lymph node metastasis (p < 0.01). Next, we examined the associations of individual biomarkers with lymph node metastasis. Multivariate analysis showed that moderately differentiated adenocarcinoma was significantly associated with lymph node metastasis (p < 0.05). Conclusions: Our findings showed that expression patterns of CAF markers and EMT-related proteins may allow for stratification of patients into risk categories for lymph node metastasis in SiCRC.

Analysis of cancer-associated fibroblasts and the epithelial-mesenchymal transition in cutaneous basal cell carcinoma, squamous cell carcinoma and malignant melanoma

Activated cancer-associated fibroblasts (CAFs) and fibroblasts that have undergone the epithelial-mesenchymal transition (EMT) in cancer stroma contribute to tumor progression and metastasis. However, no reports have investigated the CAF phenotype and its clinicopathological relevance in cutaneous malignant tumors, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and malignant melanoma (MM). Here, we investigated the CAF phenotype in cutaneous malignant tumors based on their histology and immunohistochemical expression of CAF-related markers, including adipocyte enhancer-binding protein 1 (AEBP1), podoplanin, platelet-derived growth factor receptor α (PDGFRα), PDGFRβ, fibroblast activating protein (FAP), CD10, S100A4, α-smooth muscle actin (α-SMA), and EMT-related markers (Zeb1, Slug, and Twist). In addition, we assessed the role of the CAF phenotype in cutaneous malignant cancers using hierarchical cluster analysis. Consequently, 3 subgroups were stratified based on the expression pattern of CAF- and EMT-related markers. Subgroup 1 was characterized by low expression of AEBP1, PDGFRα, PDGFRβ, FAP and Slug, whereas subgroup 2 was closely associated with high expression of PDGFRβ, S100A4 and Twist. In addition, high expression levels of podoplanin, PDGFRβ, CD10, S100A4, α-SMA, Zeb1, Slug and Twist were observed in subgroup 3. High expression of CD10 was commonly found in all 3 subgroups. These subgroups were correlated with histologic subtypes, that is, subgroup 1, MM; subgroup 2, BCC; and subgroup 3, SCC. We suggest that the expression pattern of CAF- and EMT-related proteins plays crucial roles in the progression of BCC, SCC, and MM.

Correlation between CT morphologic appearance and histologic findings in colorectal liver metastasis after preoperative chemotherapy

PurposeRadiological evaluation of the efficacy of preoperative chemotherapy for colorectal liver metastasis (CRLM) is the most important tool for determining treatment strategies. The aim of this study was to identify a correlation between morphologic appearance on computed tomography (CT) and histologic findings of CRLM after preoperative chemotherapy.MethodsWe examined 47 patients who had undergone a first hepatic resection for CRLM after preoperative chemotherapy and had received contrast-enhanced CT scans. We assessed the morphologic appearance of the overall attenuation based on metastases changing from heterogeneous to mixed and homogenous lesions, the tumor–liver interface, and the peripheral rim enhancement on CT. Histologic parameters included usual necrosis (UN), infarct-like necrosis (ILN), three-zonal change, dangerous halo, mucous lake, shape of ILN, dominant type of necrosis, and presence of viable tumor cells. The relationship between morphologic appearance and histologic findings was evaluated.ResultsCT overall attenuation revealed that UN predominance was more common in the heterogeneous group than in the mixed and homogeneous groups (P = 0.011). The frequency of ILN increased sequentially from ill-defined to variable and sharp at the tumor–liver interface (P = 0.038), and the frequency of UN decreased sequentially from present to partially resolved and completely resolved in the peripheral rim enhancement (P = 0.023). The histologic presence of viable tumor cells was closely associated with the tumor–liver interface (P = 0.0003) and the peripheral rim enhancement (P = 0.004).ConclusionsCT morphologic appearance of CRLM after preoperative chemotherapy is correlated with histologic findings regarding necrosis.

Case of gastric neuroendocrine carcinoma showing an interesting tumorigenic pathway

Here, we report a case of gastric neuroendocrine carcinoma showing an interesting tumorigenic pathway. A 57-year-old Japanese woman presented with epigastric tenderness, and distal gastrectomy was performed. In the surgical specimen, histologically, the tumor tissue was composed of three subtypes of tumor components showing different histological architecture and cellular atypia, diagnosed as neuroendocrine tumor (NET) G2, NET G3, and neuroendocrine carcinoma (NEC) components. Immunohistochemically, the Ki-67-positive rates of NET G2, NET G3, and NEC components were 6.5%, 99.5% and 88.1%, respectively. Although allelic imbalance (AI) on chromosomes 1p, 3p, 8q, TP53, 18q and 22q was commonly found in all components, AI of 4p was found in NET G3 and NEC components (but not in the NET G2 component). In contrast, AIs of 5q and 9p were found in only the NEC component. Thus, we showed the progression from NET G2 to NEC, via NET G3, within the same tumor.

Clinicopathological and molecular stability and methylation analyses of gastric papillary adenocarcinoma

The molecular alterations and pathological features of gastric papillary adenocarcinoma (GPA) remain unknown. We examined GPA samples and compared their molecular and pathological characteristics with those of gastric tubular adenocarcinoma (GTA). Additionally, we identified pathological and molecular features of GPA that vary with microsatellite stability. In the present study, samples from 63 GPA patients and 47 GTA patients were examined using a combination of polymerase chain reaction (PCR)-microsatellite assays and PCR-pyrosequencing in order to detect microsatellite instability (microsatellite instability, MSI; microsatellite stable, MSS), methylation status (low methylation, intermediate methylation and high methylation level), and chromosomal AI in multiple cancer-related loci. Additionally, the expression levels of TP53 and Her2 were evaluated using immunohistochemistry. GTA and GPA are statistically different in their frequency of pathological features, including mucinous, poorly differentiated and invasive micropapillary components. Clear genetic patterns differentiating GPA and GTA could not be identified with a hierarchical cluster analysis, but microsatellite stability was linked with TP53 and Her2 overexpression. Methylation status in GPA was also associated with the development of high microsatellite instability. However, no pathological differences were associated with microsatellite stability. We suggest that although molecular alterations in a subset of GPAs are closely associated with microsatellite stability, they play a minor role in GPA carcinogenesis.