Most are of serous or mucinous type with other morphological variants being much more uncommon.
The present study revealed ALDH1A1 to be expressed predominantly in mucinous and endometrioid epithelial cancer cells, but not in most of the serous and clear cell cancer cells.
A variable expression of MGB-2 was observed among different tumor histotypes: the protein was undetectable in most of the serous tumors (44 out of 54, 81%) independently from their primary or metastatic origin, as well as in mucinous (2 out of 3, 67%) and undifferentiated adenocarcinomas (4 out of 5, 80%).
Most tumors were of serous histotype (65%).
The most common type of serous neoplasm, the microlacunar type, has a characteristic imaging appearance on CT and MRI[ 2– 4].
Most of them were serous carcinoma, suggesting de novo carcinogenesis, whereas there were no cases of mucinous carcinoma.
Furthermore, the results support the suggestion of Prat [ 4] that low-grade serous carcinomas can be defined as uncommon ovarian carcinomas that show a noninvasive serous borderline component, and that they most likely reflect progression of serous borderline tumors beyond microinvasion.
The gene expression data used to estimate gene expression in ovarian tumors included cDNA microarray profiles of 72 ovarian tumors, of which most were late stage tumors of serous histology (manuscript in preparation).
Most of the patients had serous histotype (76.7%), and poor grade of differentiation (80.6%).
While most of the samples are serous adenocarcinomas, there are a smaller number of tumors of other types, including clear cell carcinoma, endometrioid adenocarcinoma, granulosa cell tumor, and Mullerian mixed tumor (see Additional file 2).
