Early genetic studies of quantitative trait loci for mouse cancer susceptibility with homologous regions in human cancers pointed to recurrent PTPRJ deletions, LOH, and missense mutations in small cohorts of colorectal (49%), lung (50%), and breast (78%) carcinomas in addition to a correlation between PTPRJ LOH and colorectal cancer progression [61, 62]. The gene discussed is PTPRJ; the disease is colorectal cancer.