SPINK1 and prostate intraepithelial neoplasia: The modules potentially imply different pathological signals in prostate cancer progression, including early tumorigenesis of PIN expressing high levels of NPY [94], proliferation, metastasis, and invasion of tumor with overexpression of SPON2 and TFF3 in PIN and cancer cells compared to normal glands [95, 96], and unique alterations in cancer cells such as elevated expression of SPINK1 [97].