Transforming growth factor-beta1 genotype in sporadic breast cancer patients from India: status of enhancer, promoter, 5'-untranslated-region and exon-1 polymorphisms.
TGFBR1(*)6A carrier status was further associated with a high-grade sporadic breast cancer (odds ratio: 2.27; 95% confidence interval: 1.01-5.11; P=0.049).
BRCA2-associated breast cancer is more sensitive to standard first-line chemotherapy for metastatic breast cancer in comparison with sporadic breast cancer, especially to anthracyclines.
Reduced folate carrier 1 (RFC1) G80A and methylenetetrahydrofolate reductase (MTHFR) C677T were associated with risks of 1.34 (95% CI 1.01-1.79)- and 1.84 (95% CI 1.14-3.00)-folds, respectively, for sporadic breast cancer while cytosolic serine hydroxymethyl transferase (cSHMT) C1420T was associated with reduced risk (OR 0.71, 95% CI 0.53-0.94).
BRCA1 protein-negative tumours were more frequently basal marker-positive and ER-negative, highlighting the 'BRCAness' of sporadic breast cancer with loss of BRCA1 protein expression through promoter hypermethylation similar to hereditary breast cancer with BRCA1 mutations.
BRCA1 promoter methylation is a common mechanism of BRCA1 gene aberration in sporadic breast cancer and is predictive for better response to anthracycline-based therapies.
BRCA1 mutation testing may be useful in clinically sporadic breast cancer patients with medullary features to identify potential mutation carriers independently from intrinsic molecular subtype.