LPAR1 and triple-negative breast carcinoma: LPAR1 and LPAR6 gene expression were highest in ER+HER2– (estrogen-receptor-positive, human-epidermal-growth-factor-receptor-negative) tumors and lowest in TNBC (triple negative breast cancer) tumors in all three cohorts, while this pattern was reversed for LPAR2 and LPAR3 (all p < 0.001, Figure 2A).