As expected, the region target by RET probes had two copies in all normal samples (blood sample and non-tumoral thyroid tissue from MTC patients and blood samples from healthy individuals), and also two copies in CCH (Fig. 1a-c). On the other hand, the RET gene was partially duplicated in MTC samples (Fig. 1d), whereas it was fully duplicated in two medullary thyroid cell lines (TT and MZ-CR-1) (Fig. 1 e-f). Here, RET is linked to medullary thyroid gland carcinoma.