Hence, the mRNA 5-HT2A levels are elevated in ovarian cancer cells compared to normal ovarian cells [67], while the expression of 5-HT1A, 5-HT1B, 5-HT2B and 5-HT4 receptors were found elevated in ovaries, in benign and borderline tumors (i.e., epithelial fraction), in non-invasive cancer cells, but strongly decreases in invasive cancer cells [68]. Here, HTR1B is linked to cancer.