We have previously shown that an inversion of chromosome 10, inv(10)(q11.2q21), is responsible for the generation of the RET/PTC1.     ///    "The tk domain of proto-RET can be fused either with the D10S170 gene generating the RET/PTC1 transforming sequence or with sequences belonging to the gene encoding the regulatory subunit RIA of c-AMP-dependent protein kinase A, thus forming the RET/PTC2 oncogene. "