PLoS ONE: The KRAS-Variant Is Associated with Risk of Developing Double Primary Breast and Ovarian Cancer (study of pts with both ovarian and breast cancers)

Blogger's Note: the other cancers (KRAS mutations) referred to beyond ovarian and breast cancers include references to lung and melanoma cancers; KRAS mutations have been established in colorectal cancers, however, there are no references on this particular subject within this research article regarding Lynch Syndrome -
an ongoing area of specific research (re: KRAS/Lynch Syndrome/blog posting of May 16, 2012 Jnl ASCP)
                                      ~~~~~~~~~~~~~~~~~~~
PLoS ONE: The KRAS-Variant Is Associated with Risk of Developing Double Primary Breast and Ovarian Cancer


Table 1. The KRAS-variant is significantly associated with uninformative breast and ovarian cancer patients.
doi:10.1371/journal.pone.0037891.t001

Purpose

A germline microRNA binding site-disrupting variant, the KRAS-variant (rs61764370), is associated with an increased risk of developing several cancers. Because this variant is most strongly associated with ovarian cancer risk in patients from hereditary breast and ovarian families (HBOC), and with the risk of premenopausal triple negative breast cancer, we evaluated the association of the KRAS-variant with women with personal histories of both breast and ovarian cancer, referred to as double primary patients.

Conclusions

These findings further validate the importance of the KRAS-variant in breast and ovarian cancer risk, and support the association of this variant as a genetic marker for HBOC families previously considered uninformative.

Introduction 

Hereditary breast and ovarian cancer (HBOC) syndrome is an inherited cancer-susceptibility syndrome marked by an increased risk of developing both ovarian cancer and breast cancer [1]. Families generally considered as having HBOC syndrome are those with multiple family members that have one of these cancers, especially at young ages, or an individual with a cancer in both organs, a “double primary” patient. While this is a relatively rare presentation, a substantial number of women develop both breast and ovarian primaries over their lifetime. While BRCA1 and BRCA2 are strongly associated with HBOC syndrome [2], a large number of HBOC families and women with double primary cancer do not have detectable genetic mutations (herein referred to as “uninformative” patients).
The chances of identifying a mutation causative for HBOC increase when testing individuals diagnosed with double breast/ovarian primaries [3]–[5]. However, a recent report suggests that the rates of BRCA mutations are not higher in a patient with a double primary without a family history than that for isolated first degree relative pairs with single primaries (14% versus 17% with mutations, respectively) [4]. This supports the importance of family history even in patients with double primary cancers. Although BRCA mutations were found in 49% of double primary patients in this recent analysis, it should be noted that this indicates that over half of double primary patients do not have a known genetic cause for their disease. This is consistent with other reports of these patients [3], [5].............The goal of this study was to determine the association of the KRAS-variant with women with double primary breast and ovarian cancer, to further validate the association of this variant with HBOC families. Findings here support the importance of the KRAS-variant in uninformative HBOC families as well as in predicting the risk of multiple primary cancers in women.......

Association of the KRAS-variant with Multiple Cancers in All Patients

Because the KRAS-variant has been found to be associated with an increased risk for other cancers besides breast and ovarian cancer [11], [15] we tested the hypothesis that the KRAS-variant would predict for an increased risk of developing additional cancers in this double primary cohort, regardless of BRCA mutation status. For 183 of the patients in our study where this information was available, 79.2% (n = 145) had reported just the two cancers (breast and ovarian), 12.0% (n = 22) had two separate primary breast cancers and also ovarian cancer, and 8.7% (n = 16) had cancer in an additional organ outside of the breast and ovary (triple primary).