Cytoplasmic and stromal expression of laminin γ 2 chain correlates with infiltrative invasion in ovarian mucinous neoplasms of gastro-intestinal type

Ovarian mucinous neoplasms of gastro-intestinal type (GI-type) are known to be a heterogeneous tumor composed of benign, borderline and non-invasive and invasive malignant lesions. The presence of infiltrative invasion is also known to be an important prognostic factor of this neoplasm. Laminin γ 2 chain, known to stimulate tumor cell invasion and migration, has not been sufficiently investigated in ovarian mucinous neoplasms. The purpose of this study was thus to clarify the role of laminin γ 2 in ovarian mucinous neoplasms of GI-type. We selected each morphological phase of tumor development from 61 cases of mucinous neoplasms of the GI-type: 55 adenoma lesions, 60 borderline lesions, 20 microinvasive lesions, 17 intraepithelial carcinoma lesions, 38 expansile invasive carcinoma lesions, 19 infiltrative invasive carcinoma lesions and 5 mural nodules lesions; and evaluated the localization of laminin γ 2 in the lesions using immunohistochemical method. The staining pattern was classified into i) basement membranous (BM), ii) cytoplasmic (CYT) and iii) stromal (S) pattern. The BM pattern was characteristic in adenoma, borderline, and interaepithelial and expansile invasive carcinoma lesions. The CYT and S patterns were characteristic in infiltrative invasive lesions. The staining pattern of mural nodules was similar to that of infiltrative invasion. The infiltrative invasion of GI-type ovarian mucinous neoplasms may be promoted by cytoplasmic and/or stromal expression of laminin γ 2 chain.