Immunohistochemical analysis of IQGAP2 in ovarian cancer

IQ motif-containing GTPase-activating protein 2 (IQGAP2) was regarded as a tumor suppressor in some cancers, but its expression pattern in various histological subtypes of ovarian cancer has not been investigated. Immunohistochemical staining for IQGAP2 was conducted with two human ovarian tissue microarrays containing 250 ovarian tumors and 39 normal ovarian tissues in total. Positive staining of IQGAP2 was observed in cytoplasm as well as on membrane. IQGAP2 was expressed in 48.7% of normal ovarian tissues, 37.9% of serous cancers, 66.7% of mucinous cancer, 71.4% of endometrioid cancers, 100% of clear cell cancers, 25% of endodermal sinus tumors, and immature teratomas. Contrarily, IQGAP2 was absent in dysgerminomas, transitional, and granulosa cell tumors. The mean IQGAP2 immunohistochemical composite scores were 1.92 for normal ovarian tissues,1.69 for serous cancers, 4.51 for mucinous cancers, 3.00 for endometrioid cancers, 7.71 for clear cell cancers, 0.25 for endodermal sinus tumors, and 1 for immature teratomas. Compared with normal ovarian tissues, the overall positivity of IQGAP2 in clear cell cancers and the mean composite scores of IQGAP2 in clear cell and mucinous cancers were significantly higher, while the mean composite scores of IQGAP2 in dysgerminomas, endodermal sinus tumor, and granulosa cell tumors was significantly lower. The authors concluded that IQGAP2 might serve as a tumor suppressor in dysgerminomas, endodermal sinus tumor, and granulosa cell tumors of ovary. Understanding the role of IQGAP2 in the pathogenesis of ovarian cancers necessitates further study.

Ovarian cancer; Immunohistochemistry; IQGAP2

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