p53 and p16^INK4A Mutations during the progression of glomus tumor

Abstract

Glomus tumors are significantly rare tumors of carotid body. The great majority of these tumors are benign in character. Here we present two brothers with hereditary glomus jugulare tumor who had consanguineous parents. Radiotherapy was applied approximately 8 and 10 years ago for treatment in both cases. Eight years later, one of these cases came to our notice due to relapse. The mutation pattern of p53, p57^KIP2, p16^INK4A and p15^NK4B genes which have roles in the cell cycle, was analyzed in tumor samples obtained from the two affected cases in the initial phase and from one of these cases at relapse. The DNA sample obtained from the case in initial diagnosis phase revealed no p53, p57^KIP2, p16^INK4A or p15^INK4B mutation. He is still in remission phase. Despite the lack of p53, p57^KIP2, p16^INK4A and p15^INK4B mutation at initial diagnosis the tumor DNA of the other case in relapse revealed p53 codon 243 (ATG→ATC; met→ile) and p16 codon 97 (GAC→AAC; asp→asn) missense point mutations. No loss of heterozygosity in p53 and p16^INK4A was observed by microsatellite analysis of tumoral tissues in these cases. P53 and p16^INK4A mutations observed in relapse phase were in conserved regions of both genes. No previous reports have been published with these mutations in glomus tumor during progression. The mutation observed in this case may due to radiotherapy. In spite of this possibility, the missense point mutations in conserved region of p53 and p16^INK4A genes may indicate the role of p53 and p16^INK4A in tumor progression of glomus tumors.