CLDN18 and invasive ductal breast carcinoma: In the BC dataset of Turashvili’s study [38], CLDN18 was downregulated in invasive ductal breast carcinoma with a fold change of –2.301 (p = 1.89E-04) and CLDN23 was downregulated in invasive lobular breast carcinoma with a fold change of –3.776 (p = 0.025).