GENETIC OF THYROID CANCER FAMILIAL NON MEDULLARY THYROID CANCER

Abstract

Differentiated non-medullary thyroid cancer (NMTC) is mostly sporadic, but the recurrence of familial form of the disease has been reported. Short or dysfunctional telomeres have been associated with familial benign diseases and familial breast cancer. We aimed to study the telomere-telomerase complex in familial NMTC (FNMTC). The genetic analysis included the measurement in the peripheral blood of relative telomere length (RTL), telomerase reverse transcriptase (hTERT) gene amplification, hTERT mRNA expression, telomerase protein activity and search of hTERT or TERC (telomerase RNA component) gene mutations. We, also, studied telomeric fusions and associations as well as other chromosomal fragility features by conventional and molecular cytogenetic analyses, in phytohemagglutinin stimulated T-lymphocytes from familial patients, unaffected family members, sporadic PTC patients and healthy subjects. We found that, telomere lenght was significantly shorter in the blood of familial patients compared to sporadic PTCs, healthy subjects, nodular goiter and unaffected siblings. hTERT gene amplification was significantly higher in FNMTC patients compared to the other groups and, in particular, it was significantly greater in offspring with respect to parents. hTERT mRNA expression as well as telomerase activity were significantly higher in FNMTC patients compared to sporadic In addition, we demonstrated that familial patients have a significant increase in spontaneous telomeric associations and telomeric fusions compared to healthy subjects and sporadic cases. Q-FISH analysis demonstrated that familial cases display a significant decrease in the telomeric PNA-FISH signal intensity in metaphase chromsome. Our study demonstrates that patients with FNMTC display an imbalance of the telomeretelomerase complex in the peripheral blood.