Browsing by Author "Hennessy, Bryan T."

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    Identifying homologous recombination deficiency in breast cancer: genomic instability score distributions differ among breast cancer subtypes
    (Springer, 2023) Lenz, Lauren; Neff, Chris; Solimeno, Cara; Cogan, Elizabeth S.; Abramson, Vandana G.; Boughey, Judy C.; Falkson, Carla; Goetz, Matthew P.; Ford, James M.; Gradishar, William J.; Jankowitz, Rachel C.; Kaklamani, Virginia G.; Marcom, P. Kelly; Richardson, Andrea L.; Storniolo, Anna Maria; Tung, Nadine M.; Vinayak, Shaveta; Hodgson, Darren R.; Lai, Zhongwu; Dearden, Simon; Hennessy, Bryan T.; Mayer, Erica L.; Mills, Gordon B.; Slavin, Thomas P.; Gutin, Alexander; Connolly, Roisin M.; Telli, Melinda L.; Stearns, Vered; Lanchbury, Jerry S.; Timms, Kirsten M.; Medicine, School of Medicine
    Purpose: A 3-biomarker homologous recombination deficiency (HRD) score is a key component of a currently FDA-approved companion diagnostic assay to identify HRD in patients with ovarian cancer using a threshold score of ≥ 42, though recent studies have explored the utility of a lower threshold (GIS ≥ 33). The present study evaluated whether the ovarian cancer thresholds may also be appropriate for major breast cancer subtypes by comparing the genomic instability score (GIS) distributions of BRCA1/2-deficient estrogen receptor-positive breast cancer (ER + BC) and triple-negative breast cancer (TNBC) to the GIS distribution of BRCA1/2-deficient ovarian cancer. Methods: Ovarian cancer and breast cancer (ER + BC and TNBC) tumors from ten study cohorts were sequenced to identify pathogenic BRCA1/2 mutations, and GIS was calculated using a previously described algorithm. Pathologic complete response (pCR) to platinum therapy was evaluated in a subset of TNBC samples. For TNBC, a threshold was set and threshold validity was assessed relative to clinical outcomes. Results: A total of 560 ovarian cancer, 805 ER + BC, and 443 TNBC tumors were included. Compared to ovarian cancer, the GIS distribution of BRCA1/2-deficient samples was shifted lower for ER + BC (p = 0.015), but not TNBC (p = 0.35). In the subset of TNBC samples, univariable logistic regression models revealed that GIS status using thresholds of ≥ 42 and ≥ 33 were significant predictors of response to platinum therapy. Conclusions: This study demonstrated that the GIS thresholds used for ovarian cancer may also be appropriate for TNBC, but not ER + BC. GIS thresholds in TNBC were validated using clinical response data to platinum therapy.