Japan Society for the Promotion of Science.

Abstract. Angiogenesis is essential for tumor growth and metastasis. CD105 is reportedly a specific marker for tumor angiogenesis. It has been demonstrated that monoclonal antibodies to CD105 have high affinity for activated endothelial cells. A relationship between metastasis and microvessel density (MVD), as an indicator of neovascularization, has been identified in patients with colorectal cancer as shown by the presence of monoclonal antibodies to CD105. However, data on potentially confounding factors such as lymphatic and vascular infiltration and tumor size are lacking. We further investigated the relationship between MVD and distant metastasis, along with potentially confounding clinicopathological factors, to more precisely characterize this relationship. In this retrospective study, we analyzed colorectal cancer specimens surgically or endoscopically resected from January to September 2009. We defined MVD as the number of microvessels stained by monoclonal antibodies to CD105 per x400 field. Selected clinicopathological factors were analyzed and stepwise multivariate logistic regression was performed to identify independent risk factors for distant metastasis. We analyzed 129 lesions. The median follow-up time was 34 months (range, 6-85 months) in patients with distant metastasis and 61 months (range, 60-86 months) in those without distant metastasis. At the time of resection or during subsequent follow-up, 32 patients had distant metastases. The MVD was significantly greater in patients with than without distant metastases (mean ± standard deviation: 10.4±4.9 vs. 7.6±3.3, P=0.008; Welch's t-test). Stepwise multivariate logistic regression indicated that MVD, regional lymph node metastasis, and tumor size were independent risk factors for distant metastases. Combining assessment of monoclonal antibodies to CD105-positive MVD with assessment of regional lymph node metastasis and tumor size may help to identify patients who need more intensive surveillance after surgery for colorectal cancer.

Gene mutations are involved in the development of malignant mesothelioma. Important mutations have been identified in the genes for cyclin-dependent kinase inhibitor 2A (p16) alternative reading frame, breast cancer-associated protein 1 (BAP1) and neurofibromatosis type 2 (NF2). Previously, the utility of detecting the loss of BAP1 by immunohistochemistry (IHC) and p16-deletion by fluorescence in situ hybridization has been identified in several studies. However, NF2-associated examinations have not been performed. The present study aimed to evaluate the expression of yes-associated protein 1 (YAP1) and tafazzin (TAZ) protein, which are associated with NF2 gene mutations, in malignant mesothelioma (MM) and reactive mesothelial cells (RMCs). Formalin-fixed paraffin-embedded tissues from 31 MM and 33 RMC samples were analyzed. The expression of YAP1 and TAZ protein were examined by IHC. Positivity for YAP1 was identified 27/31 MM and 15/33 RMC samples. Positivity for TAZ was identified in 28/31 MM and 18/33 RMC samples. Using the optimal cutoff points determined by the receiver operating characteristic curve, a positive IHC result for YAP1 and TAZ was 74% sensitive and 94% specific for detecting MM. The results indicate that increased expression of YAP1 and TAZ may be associated with mesothelial tumorization, and aid in the diagnosis of MM.

T1 colorectal carcinomas (CRCs) are an initial site of metastatic spread. Various risk factors for lymph node metastasis have been investigated in T1 CRCs. However, the major step in the entire process of metastasis remains unclear. In terms of carcinoma invasion and metastasis, matrix metalloproteinases (MMPs) have recently gained increasing attention. Notably, MMP-7 is frequently overexpressed in CRCs, but its implication has not been determined in T1 CRCs yet. The present study aimed to clarify the associations between the pathological risk factors of T1 CRCs and MMP-7. In the current study, 211 lesions of T1 CRC that were resected endoscopically or surgically at Showa University Northern Yokohama Hospital (Yokohama, Japan) between April 2008 and December 2009 were retrospectively analyzed. MMP-7 was immunostained and evaluated by its frequency of expression. Pathological factors of T1 CRCs were analyzed in association with MMP-7 expression. Furthermore, the ultrastructural alterations of carcinoma invasion were examined using low vacuum-scanning electron microscopy (LV-SEM). MMP-7 expression was associated with venous invasion (P=0.005), and LV-SEM revealed the disappearance of the normal structure of collagen and elastic fibers of veins invaded by tumor cells expressing MMP-7. At the invasive front, MMP-7 has a vital role in carcinoma invasion, correlating with venous invasion of T1 CRCs.

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