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Yamamoto S.,Department of National Defence | Tsuda H.,National Cancer Center Hospital | Takano M.,National Defence Medical College | Iwaya K.,Department of National Defence | And 2 more authors.
Journal of Pathology | Year: 2011

Clear cell adenocarcinoma (CCA), a highly lethal histological subtype of ovarian carcinoma, is a type of human cancer with a high frequency of activating mutations in the PIK3CA gene. In this study, we aimed to determine how these mutations contribute to tumour development of CCAs. Exons 9 and 20 of the PIK3CA gene were analysed by direct genomic DNA sequencing of 23 CCAs with synchronous putative precursor lesions (ie endometriosis adjacent to carcinoma, with or without cytological atypia) and their mutational statuses were compared. Somatic mutations of the PIK3CA gene were detected in 10/23 (43%) carcinomas and in all cases the type of mutation was H1047R in the kinase domain. The identical H1047R mutation was also detected in the coexisting endometriotic epithelium, adjacent to the CCAs, in nine of ten (90%) cases. Moreover, in six of the nine lesions, the H1047R mutation was identified even in the endometrioses lacking cytological atypia. These findings provide evidence that mutations of the PIK3CA gene occur in the putative precursor lesions of CCA, strongly suggesting that they are very early events in tumourigenesis, probably initiating the malignant transformation of endometriosis. A specific kinase inhibitor to mutated PIK3CA may potentially be an effective therapeutic reagent against these carcinomas. Copyright © 2011 Pathological Society of Great Britain and Ireland. Copyright © 2011 Pathological Society of Great Britain and Ireland. Source


Yamamoto S.,Department of National Defence | Tsuda H.,Department of National Defence | Tsuda H.,National Cancer Center Hospital | Miyai K.,Department of National Defence | And 2 more authors.
Histopathology | Year: 2010

Aims: To identify the key cell-cycle dysregulations in the development of endometriosis-associated ovarian clear cell adenocarcinoma (CCA). Methods and results: Expression of p27Kip1-interacting cell-cycle regulators, such as p27Kip1 itself, Skp2, cyclin-dependent kinase subunit 1 (Cks1), cyclin A and cyclin E, and Ki67 labelling index (LI), were analysed by immunohistochemistry in 23 CCAs with 36 endometriotic or atypical endometriotic lesions adjacent to CCA from a cohort of 23 patients, and in 31 cases of solitary endometriosis. The cell-cycle regulators examined were overexpressed (Skp2, Cks1, cyclin A and cyclin E; P < 0.01, each) or down-regulated (p27Kip1, P = 0.044) significantly more frequently in the CCAs than in the adjacent endometriosis. The frequency of Skp2 overexpression was significantly higher in atypical endometriosis than in endometriosis, and the frequency of Skp2 and cyclin A overexpression was significantly higher in CCA than in atypical endometriosis (P < 0.01, each). Mean Ki67 LI increased from endometriosis (8.4%) through atypical endometriosis (21.4%) to CCA (46.9%), with statistical significance between each component (P < 0.01, each). The frequency of cell-cycle regulator expression and mean Ki67 LIs were not significantly different between solitary endometriosis and endometriosis adjacent to CCA. Conclusions: Alteration of the p27Kip1-interacting cell-cycle regulators appeared strongly involved in the progression of endometriosis-associated ovarian clear cell carcinogenesis through increasing cell proliferative activity. © 2010 Blackwell Publishing Limited. Source

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