HTR4 and cancer: They found that HTR4 is associated with the late progression of hormone refractory prostate cancer, possibly due to the paracrine/autocrine mechanism of HTR4-induced hormones or growth factors, and HTR4 is also associated with estrogen receptor α and estrogen receptor β. The overexpression of the receptor of the neuroendocrine cell product may be related to the occurrence of hormone refractory prostate cancer, which provides a new direction for the trigonometric relationship between cancer neuroendocrine sex hormones.