ESR1 and breast carcinoma: We found that grade (p < 0.001), ER status (p <0.001), PR status (p < 0.001), IHC based intrinsic subtypes (p < 0.001), AJCC 6th staging (p = 0.03), T status (p = 0.01) and brain metastasis (p = 0.03) significantly differed between GRCC and non-GRCC carcinomas of the breast; although only a single case of GRCC with brain metastasis was available in our analysis.