CYP19A1 and hepatocellular carcinoma: In the HCC 1937 cell line, which possesses a mutation in the BRCA1 gene, the presence of mRNA expression of the leptin receptor was found in the two isoforms analyzed (long and homologous isoform), as in the MDA MB 231 cell line, no expression of the estrogen receptor or CYP19A1 was found, as it was also a negative triple-negative breast cancer cell line.