In contrast, in several other tumor cell line, PACAP has been shown to inhibit growth, like MCF-7 breast cancer cells (126), a negative regulator of cervical carcinoma as overexpression of the PACAP gene in cervical cancer cell lines lacking PACAP expression significantly inhibited cell growth and induced apoptosis (217), is a pro-apoptotic factor in choriocarcinoma cells (215), and inhibits the growth of myeloma, leukemia and medulloblastoma cells (228–230). This evidence concerns the gene ADCYAP1 and breast cancer.