We analyzed the prevalence of BRAF point mutations and RET/PTC rearrangements in 55 post-Chernobyl papillary carcinomas, compared with 82 sporadic papillary carcinomas.     ///    "Sporadic papillary carcinomas revealed a clearly distinct pattern, with 37% of tumors harboring BRAF mutations and 20% RET/PTC rearrangements. "    ///    Radiation-induced tumors demonstrated a low prevalence (4%) of BRAF point mutations and high prevalence (58%) of RET/PTC rearrangements. 