Dr. Zarbl's laboratory used quantitative trait locus (QTL) mapping in genetic a backcross to identify a rat mammary carcinoma susceptibility locus (Mcs) that was highly linked to susceptibility to chemically induced mammary carcinogenesis in the Fischer 344 rat. Candidate gene analysis identified FRY as the tumor suppressor gene that mediates its effects by suppressing epithelial mesenchymal transition. His laboratory at Robert Wood Johnson Medical School (UMDNJ) has data indicating that that the human FRY gene encodes a breast cancer suppressor gene. FRY may thus be the first candidate human tumor suppressor gene identified by QTL mapping in a rodent model of cancer that also has relevance to human cancer. Collaborative studies demonstrated that altered expression of FRY is highly correlated with breast cancer, histopathology, hormone receptor status, and Elston grade.