Pumilio1 (Pum1) and Pumilio 2 (Pum2) share high structural similarity but have overlapping targets and functions, such as embryonic development, germ cell development, cell cycle, neural response, memory, and so on [77–79], particularly in neurological degeneration [79] and acquired resistance in cancer [80,81], including ovarian cancer [82], pancreatic cancer [83], breast cancer [84], and colon cancer [85]. The gene discussed is PUM2; the disease is breast cancer.