IL7 is about 25 kDa and the specific gene is located in the locus 8q12–13, this interleukin can interact with the surface receptor interleukin-7 receptor (IL7R); which contains the IL7R alpha chain; errors in the expression of IL7 and its receptor are linked to breast cancer [210] and this can promote survival and cancer cell growth in vitro and poor prognosis in humans [207]. The gene discussed is IL7R; the disease is cancer.