Abstract 2609: Addition of ER and PTEN, but not cytokeratins, aids identification for BRCA1 carriers in Malaysian breast cancer patients

Abstract

Background: Given that BRCA1 carriers are more likely to develop triple negative breast cancers (TNBC) and that current risk assessment models underestimate BRCA carriers in Asian populations, we have sought to determine the prevalence of BRCA mutations amongst TNBC patients and whether addition of pathological features improves the sensitivity of the Manchester scoring method of BRCA risk assessment. Methods: A total of 399 patients from the Malaysian Breast Cancer Genetic Study were fully analysed for BRCA1 and BRCA2 mutations, including 101 patients with TNBC. Pathological features, including estrogen receptor (ER) and PTEN status were assessed and included in a modified Manchester scoring method. Results: Our study in an Asian series of triple negative breast cancer patients has demonstrated that 22% [22/101] of patients have germline mutations in BRCA1 [18/101] and BRCA2 [4/101]. We find that amongst patients who were diagnosed with breast cancer aged 36-50 but with no family history of breast or ovarian cancer, the prevalence of BRCA mutations was similar amongst those who developed triple negative breast cancer (7%) and non-TNBC (7%). By contrast, in two other groups of patients (a) those who were diagnosed with breast cancer β35 years old with no family history of these cancers, and (b) those with family history of breast cancer, the prevalence of mutations was higher in those with TNBC compared to those with non-TNBC [29% and 11%; p=0.07; and 40% and 14%; p=0.001 respectively]. Furthermore, we find that incorporation of estrogen-receptor status improves the sensitivity of the Manchester Scoring method [38% to 62%] and in particular, incorporation of the status of PTEN, further improves sensitivity [43% to 100%]. Conclusion: We find that TNBC is an important criteria for highlighting patients who may benefit from genetic testing, but that this may be most useful for individuals with early onset breast cancer (≥35 years old) or with family history of cancers. Furthermore, addition of ER and PTEN status improves the sensitivity of the Manchester scoring method and may be particularly important in the Asian context when family history is often inaccurately reported. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2609. doi:1538-7445.AM2012-2609