BRCA1 and neoplasm: When we took into account the zygosity status of BRCA1 methylation—which importantly has not been systematically addressed in the literature with respect to clinical outcomes and association with response to PARPi or platinum29,33—we observed that the zygosity of each of the four BRCA1-methylated PDX correlated with the zygostity status of the source tumor used to generate PDX, and did not change under the pressure of subsequent in vivo treatment of the PDX.