Recently, the G534E variant of the HABP2 gene was reported as the underlying genetic defect in large kindred with non-syndromic familial non medullary thyroid cancer (FNMTC), but these data were not confirmed in additional cohorts. Consistently, we found in our wide series of FNMTC that the HABP2G534E variant is frequent, but does not segregate with the disease. Nevertheless, a possible role for this gene in the pathogenesis of FNMTC cannot definitely ruled out also because contrasting but interesting expression data are available in other human tumors. To get more insights into the expression of this gene in thyroid tumor and normal tissues, HABP2 expression levels were determined by non-quantitative or quantitative Real-time PCR of RNA extracted from nine neoplastic and matched normal thyroid tissues: seven sporadic papillary thyroid cancer (PTC) cases not carrying HABP2G534E, 1 FNMTC from a member carrying HABP2G534E and 1 FNMTC from a member not carrying the variant. Immunohistochemistry for HABP2 was performed in 6 neoplastic and matched normal thyroid tissues: 2 sporadic PTC cases, 2 FNMTC from members carrying the HABP2G534E variant and 2 FNMTC from members not carrying the variant. HABP2 mRNA had a very variable expression in tissues from FNMTC, sporadic PTCs or contralateral normal tissues. In almost all cases, the gene appeared down- or up-regulated in tumors with respect to the corresponding normal tissue. At immunohistochemistry, HABP2 was expressed in both tumor and matched control tissues, without differences between sporadic and familial cases. In conclusion, our data confirm the apparent lack of co-segregation of the HABP2G534E variant with FNMTC. Nevertheless, the dysregulation of HABP2 expression found in either sporadic or familial PTCs or normal thyroid tissues, suggests potential post-transcriptional and post-translational alterations, and is consistent with similar findings in other malignancies, possibly indicating a role of this gene also in thyroid cancer.
20 - 23 May 2017
European Society of Endocrinology