Transcriptional levels of Cx43 were determined in 54 randomly selected human breast carcinoma samples, distributed into three groups (18 samples per group); group 1: ER− PR− HER2– (TNBC samples), group 2: ER− PR− HER2+, and group 3: ER+ PR+ HER2−. Here, GJA1 is linked to breast carcinoma.