The Significance Of Ras Protein Expression And Gene Mutation In Skin Pathological Scar And Scar Carcinoma Tissues

Objective:To explore the significance of Ras family (H-ras/N-ras/K-ras) protein expression and gene mutation in skin pathological scar and scar carcinoma tissues.Methods:It is used that 16 cases skin pathological scar tissues and 20 cases skin scar carcinoma tissues to compare with 10 cases normal skin tissues. The expression of H-ras, N-ras and K-ras proteins were detected by the immunohistochemical method of SP. The expression (optical density and positive area) of H-ras, N-ras and K-ras proteins were detected respectively by computerized image-analysis in normal skin epidermis, skin pathological scar epithelium and scar carcinoma tissues. Besides, DNA was extracted through the choosen samples fixed in 10% formalin and Paraffi embedded (including 14 cases skin pathological scar tissues and 14 cases scar carcinoma tissues). H-ras, N-ras and K-ras mutations in codons 12 and 13 were analyzed using PCR and sequencing. All data was input into the computer and statistically analyzed with SPSS 16.0 software.Results:(1) H-ras, N-ras and K-ras proteins showed negative or weakly positive expression in normal skin epidermis and skin pathological scar epithelium. No statistic differences of their expression were measured between normal skin epidermis and skin pathological scar epithelium (P>0.05). But the number of scar epithelium positive cells was increased compared with normal skin epidermis. (2) H-ras, N-ras and K-ras proteins showed strong positive expression in scar carcinoma tissues. Compared with normal skin group and skin scar group, the expression (optical density and positive area) of H-ras, N-ras and K-ras proteins in scar carcinoma group were statistically significant (P< 0.05). (3) Whether it is the histological type or cell differentiation, the higher differentiation shows the stronger expression of Ras protein, the lower differentiation shows the weaker expression of Ras protein in scar carcinoma tissues. The expression of Ras protein were statistically significant between well differentiated group and poorly differentiated group (P<0.05). (4) The positive signal of K-ras protein was mainly localized in the nucleus in normal skin group, and was mainly localized in the nucleus and cytoplasm in skin pathological scar group. K-ras protein showed the expression of cytoplasm in skin scar carcinoma group. It appears the displacement phenomenon that K-ras protein shift from the nucleus to the cytoplasm gradually. (5) The point mutation analysis of Ras family:DNA was extracted through the choosen 28 samples fixed in 10% formalin and Paraffi embedded. Using PCR, the 28 samples were succeed to enlarge the gene piece of H-ras, N-ras and K-ras. The codons 12 and 13 of H-ras, N-ras and K-ras genes were not examined to have the mutation after sequencing.Conclusions:(1) In skin pathological scar epithelium, the restrictive low expression of H-ras, N-ras and K-ras proteins may be some related to the hyperplasia of skin scar epithelium. (2) Compared with normal skin and skin pathological scar, the high expression of H-ras, N-ras and K-ras proteins may be related to the occurrence of skin scar carcinoma. (3) H-ras, N-ras and K-ras proteins were related to the differentiation of tumor cell, these proteins may gradually lose in the evolution of skin scar carcinoma. (4) The displacement phenomenon of K-ras proteins may be related to the occurrence of skin scar carcinoma. (5) The codons 12 and 13 of Ras family were not examined to have the mutation in skin scar carcinoma, the mutation situs of Ras family is to be further explored.