However, the cancer cells used in the aforementioned studies, such as MDA-MB-231 [34], MCF-7 [32], MMTV-PyMT [35], MMTV-Wnt1 [19], and HT-29 [26], were sensitive to the direct action of vitamin D and/or immune deficient models were used [26,34,36,37]. Here, WNT1 is linked to cancer.