The prevalence of RET/PTC activation in PTC is high and RET/PTC3 is the only type of activation identified in Hong Kong Chinese and is an important genetic event underlying the development of PTC in the population..     ///    "The presence of RET/PTC1, RET/PTC2 and RET/PTC3 activation was analyzed by RT-PCR in twenty PTC from adult patients (age range 24-63 years), one PTC from a 12-year-old boy and anaplastic carcinomas in two adult patients. "    ///    RET/PTC3 was also identified in PTC from the child and one of the two patients with anaplastic thyroid carcinoma.     ///    Seventeen PTC from adult patients (85%t) were positive for RET/PTC3.     ///    RET/PTC3 was the only activation of RET proto-oncogene identified in the samples. 