The Expression And Initiatory Mechanism Of THOC2 In Cutaneous Malignant Melanoma

Background Cutaneous malignant melanoma(CMM)is a high-grade malignant tumor derived from melanocytes,accounting for the third place in malignant skin tumors.In addition to CMM,it also affects the mucosa,lymph nodes,and internal organs.In recent years,melanoma has become a rapidly growing malignant tumor worldwide,but its specific pathogenesis has not been fully elucidated.Our research group has used the technique of isobaric tags for relative and absolute quantitation(iTRAQ)to explore the pathogenesis of let-7a,and the result showed that THOC2 may be one of the downstream target proteins.THOC2 protein,one of the major subunits of TRanscription and EXport(TREX)complex,is involved in the processes of mRNA nucleation transport,post-transcriptional processing and modification,however,its probable role in tumor genesis and development has been rarely studied.Furthermore,the epithelial-mesenchymal transition(EMT)process has been proved that its important role in growth,invasion and metastasis of tumor cells.Objective To assess the expression of THOC2 and EMT processing related molecules,E-cadherin,in CMM and the control tissue,and to explore its probable mechanism.Methods Paraffin tissue blocks of cutaneous malignant melanoma and normal skins were obtained from the Department of Dermatology,Chinese Academy of Medical Sciences,including 20 cutaneous malignant melanoma and 10 normal skins or peritumoral skins.Immunohistochemistry was performed to determine the expression of THOC2 and E-cadherin.Statistical analysis was carried out with SPSS 23.0 software by using chi-square test for comparison between two groups.Results The positive rates of THOC2 in melanoma and peritumoral normal tissues were 80%(16/20)and 20%(2/10),respectively(P=0.004<0.05).The positive rates of E-cadherin in melanoma and nevus cell nevus were 25%(5/20)and 90%(9/10),respectively(P=0.001<0.05).Conclusion Compared with the normal skin or nevus cell nevus,melanoma showed increased THOC2 expression and decreased E-cadherin expression.THOC2 can improve the progression,possibly by promoting EMT in melanoma.