chromosomal rearrangements of ret/ptc in post-chernobyl thyroid cancer

A hypothesis is proposed here that ret rearrangements in papillary thyroid cancers are related to the disease duration and tumor progression. the most common ret rearrangements are ret/ptc1 and ret/ptc3. ret/ptc1 is more prevalent in classic papillary thyroid carcinoma (ptc), its diffuse sclerosing variant, and papillary microcarcinoma; while ret/ptc3 is frequently found in less differentiated solid ptc. ret/ptc3 is associated with larger tumor size and multifocality in sporadic pediatric ptc. the ret rearrangements; especially ret/ptc3, which is frequently detected among chernobyl thyroid cancers is developed after exposure to radiation at an early age, is proposed to be a potential trigger of malignancy. there are many late-stage tumors among the first-wave chernobyl ptcs that tend to be larger and less differentiated than those detected later. the high proportion of late-stage cases shortly after the accident is explained by the neglected cases in the screening process and also by the fact that some non-exposed patients were registered as radiation-exposed. the screening was productive because of the reservoir of undiagnosed cases in the population: registered incidence of thyroid cancer (tc) among children and adolescents prior to the chernobyl disaster was low in the soviet union; compared to other developed countries. in conclusion, ret rearrangements, especially ret/ptc3, were correlated with the tumor progression. if the hypothesis defended here is correct, a low prevalence of ret/ptc3 among sporadic tc is circumstantial evidence of efficient cancer diagnosis and early detection.