For example, SPRR3, a member of the small proline-rich protein family, is under purifying selection in cancer cells (CN/CS = 0.27, p = 5.73 × 10–11, FDR = 1.91 × 10–8) and neutral selection in germline cells (pN/pS = 0.88, p = 0.75, FDR = 0.37). Here, SPRR3 is linked to cancer.