abstract: Stem Cell Pathways Contribute to Clinical Chemoresistance in Ovarian Cancer (in research)

Experimental Design: We examined 45 matched primary/recurrent tumor pairs of high-grade ovarian adenocarcinomas for expression of CSC markers ALDH1A1, CD44, and CD133 using immunohistochemistry. Tumors collected immediately after completion of primary therapy were then laser capture microdissected and subjected to a quantitative PCR array examining stem cell biology pathways (Hedgehog, Notch, TGF-β, and Wnt). Select genes of interest were validated as important targets using siRNA-mediated downregulation.

Conclusions: These data indicate that ovarian tumors are enriched with CSCs and stem cell pathway mediators, especially at the completion of primary therapy. This suggests that stem cell subpopulations contribute to tumor chemoresistance and ultimately recurrent disease.

abstract: Objectives: Published data are conflicting on the influence of cell type on prognosis in ovarian cancer. The recent separation of low-grade serous carcinoma as a distinctive cell type of ovarian cancer with an indolent behavior, in retrospect, suggests that survival in studies that have not separated this group may be inaccurate.

Blogger's Note:  the focus of this abstract is serous cell type

Conclusions:
Low-grade serous carcinoma has a significantly better prognosis than high-grade serous carcinoma and also differs with regard to substage distribution and proportion of patients optimally debulked. Because of its excellent prognosis, failure to separate low-grade serous carcinomas, notwithstanding its infrequent occurrence, can change the results of survival analyses that do not make this separation.

"Primary peritoneal" high-grade serous carcinoma is very likely metastatic from serous tubal intraepithelial carcinoma: Assessing the new paradigm of ovarian and pelvic serous carcinogenesis and its implications for screening for ovarian cancer.

CONCLUSIONS: At least half the cases of primary peritoneal high-grade serous carcinoma are associated with intraepithelial carcinoma of the fallopian tube, usually involving the fimbriae. These findings support the view that, like "primary ovarian carcinoma," what has been traditionally classified as "primary peritoneal carcinoma" is probably derived from occult high-grade serous carcinoma in the fallopian tube. These findings have important implications for ultrasound screening trials for ovarian cancer which are based on the assumption that an enlarged ovary is a very early manifestation of disease.

abstract/free full pdf access:P redictive and Prognostic Protein Biomarkers in Epithelial Ovarian Cancer: Recommendation for Future Studies Cancers

"Abstract: Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer."
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"High grade serous tumors show particular differences in terms of their development, genetic alterations and prognosis. This has led to the classification of ovarian cancer into two types: type 1 tumors, which are low grade and slowly developing (endometrioid, mucinous and low grade serous tumors), and type 2 tumors, which rapidly progress (high grade serous). In addition, the association of biomarker expression with survival varies substantially between subtypes, and can easily be overlooked in whole cohort analyses. Although these data suggest substantial differences between subtypes, until recently ovarian carcinomas were typically approached as a monolithic entity by researchers and clinicians. This practice impeded progress in understanding the biology or improving the management of the less common ovarian carcinoma subtypes. To avoid this effect, each subtype within a cohort should be analyzed individually. Therefore, molecular classifiers of ovarian cancer are of high clinical relevance in the management of these cancer patients...." cont'd