Breast Cancer Subtypes and Epigenetic Characterization of in Women from Senegal, West Africa
Mara Rendi, Kimberly H Allison, Joshua Stern, Stephen Hawes, Qinghua Feng, Nancy Kiviat. University of Washington, Seattle
Background: We have previously described the frequency of pre/postmenopausal breast cancer as well as risk factors in a large cohort of women from Senegal, West Africa. In this study, our aims were to further characterize these cancers and to determine the histology, immunohistochemical profile, and methylation status of pre- and postmenopausal breast CA in West Africans.
Design: As previously reported, 522 consecutive women presenting to the Dakar Tumor Institute, Senegal, West Africa with a breast mass were enrolled and underwent a physical examination and medical history. Needle core biopsy of the mass was performed with subsequent histologic and immunohistochemical analysis with HER2 gene amplification status in equivocal cases. Immunohistochemical results were used as a surrogate to determine the breast cancer subtypes. Additionally, the epigenetic profile of these tumors was assessed by examining the methylation status of 32 genes known to be involved in breast and other epithelial cancers.
Results: Of the 522 women enrolled, the presence of cancer was confirmed in 197, 57% of which were premenopausal, 43%, postmenopausal. 96% of cases were invasive ductal carcinoma, with cases of invasive lobular carcinoma (2%) and mixed ductal and lobular features (2%) comprising the remainder. 75% of the cancers were Grade 3, 21% were Grade 2, and 4% were Grade 1. The IHC status is as follows:
|ER+/PR+/HER2-||ER-/PR-/HER+||TN (% of TN cases also CK 5/6 +)|
|Premenopausal||40%||19%||41% (53% CK 5/6+)|
|Postmenopausal||42%||13%||45% (47% CK 5/6+)|
|Total of all cases||43%||15%||42% (67% CK 5/6+)|