Eklund L K, Lindström E, Undén A B, Lundh-Rozell B, Ståhle-Bäckdahl M, Zaphiropoulos P G, Toftgård R, Söderkvist P
Department of Cell Biology, Faculty of Health Sciences, University Hospital, Linköping University, Sweden.
Mol Carcinog. 1998 Feb;21(2):87-92. doi: 10.1002/(sici)1098-2744(199802)21:2<87::aid-mc2>3.0.co;2-l.
The human homologue of Drosophila patched (PTCH), located at chromosome 9q22.3, was recently identified as a candidate tumor suppressor gene for familial and sporadic basal cell carcinomas. Squamous cell carcinomas (SCCs) of the skin display allelic loss in this chromosomal region, which, in addition to the PTCH gene, contains the DNA repair gene xeroderma pigmentosum complementation group A (XPA). Patients with xeroderma pigmentosum are predisposed to non-melanoma skin tumors because of deficient excision repair of ultraviolet-induced DNA damage. Mutation analysis by single-strand conformation analysis and direct DNA sequencing of all 23 exons of the PTCH gene and all six exons of the XPA gene in 14 SCCs did not reveal structural alterations in any of these genes. Additionally, analysis of PTCH expression by in situ hybridization in SCCs revealed no evidence of upregulation of PTCH mRNA, confirming the lack of mutations in this gene. These findings suggest that another, yet to be identified gene or genes on chromosome 9q are involved in SCC tumorigenesis.
果蝇patched（PTCH）的人类同源物位于9号染色体q22.3，最近被鉴定为家族性和散发性基底细胞癌的候选肿瘤抑制基因。皮肤鳞状细胞癌（SCC）在该染色体区域显示等位基因缺失，除了PTCH基因外，该区域还包含DNA修复基因着色性干皮病互补组A（XPA）。着色性干皮病患者由于紫外线诱导的DNA损伤的切除修复缺陷，易患非黑素瘤皮肤肿瘤。通过单链构象分析和对14例SCC中PTCH基因的所有23个外显子和XPA基因的所有6个外显子进行直接DNA测序的突变分析，未发现这些基因中有任何结构改变。此外，通过原位杂交分析SCC中PTCH的表达，未发现PTCH mRNA上调的证据，证实该基因缺乏突变。这些发现表明，9号染色体q上另一个尚未确定的基因或多个基因参与了SCC的肿瘤发生。
