The human oncogene INTl has been mapped to chromosome band 12q13 by in situ hybridization. The precise localization of this gene is of particular interest, since the region 12q1→q14 has been reported to be involved in chromosomal rearrangements in lipomas, myxoid liposarcomas, pleomorphic adenomas, and myomas. The involvement of this region in both benign and malignant tumors suggests a common pathogenetic pathway in which changes affecting INTl may be an important step.