The Study Of The Expression And Clinical Significance Of LEF1 And TCF1(TCF7) Proteins In Nasopharyngeal Carcinoma

Background:Nasopharyngeal carcinoma(NPC)is a kind of head and neck tumor with ethnic and geographical distribution preference,mainly in east and southeast Asian and north African countries.Almost all patients with NPC are infected with Epstein-Barr virus.Data from epidemiology of China suggested that there were 42,100 and 21,320 new cases and cancer-related deaths of nasopharyngeal carcinoma in 2013,accounting for 1.14% and 0.96% of all new cancer patients and dead ones in that year respectively.With the development of diagnosis and comprehensive treatment of NPC,most of the patients are under control,but there are still some individuals suffering from distant metastasis and the prognosis is poor.The canonical Wnt/β-catenin pathway participates in the pathogenesis of the malignant tumors.β-catenin,a core component of the canonical Wnt/β-catenin signaling,playing a dual role in cells.Normally,GSK3β can regulate and phosphorate β-catenin with the help of Axin,APC and CK1α,and p-β-catenin can be degraded by ubiquitin proteasome.The lack of β-catenin in nucleus makes LEF(lymphoid enhancer factor)/TCF(Transcription factor)combine with other proteins and repress target genes,which is connected with its HMG box.The canonical pathway is activated upon binding of secreted Wnt ligands to Fzd receptors and LRP co-receptors,which inactivates GSK3β and results in stabilization and accumulation of β-catenin that then translocates into the nucleus.There,β-catenin forms an active complex with LEF/TCF proteins and transcriptional upregulates downstream genes such as CCND1,MMP7,MYCL1 and AXIN2.The abnormal activation of canonical pathway can eventually lead to proliferation,invasion and metastasis of tumor cells.As the important components of the canonical Wnt/β-catenin signaling,LEF/TCF is confirmed to be abnormal in many malignant tumors.Reports on LEF and TCF are mostly concentrated in colorectal cancer,leukemia,breast cancer and other malignant tumors,and only few researches are in NPC.When reviewing the recent literatures,we couldn’t find any paper to detect LEF1 and TCF1(TCF7)via IHC simultaneously in NPC.Based on the above background,we collected 391 NPC samples,53 nasopharyngeal noncancerous ones and 28 pairs of primary tumors and metastases of NPC,and then detected the expression LEF1 and TCF1(TCF7)with IHC in these tissues.Various statistical methods were used to analyze the relationship between the protein expression and the clinicopathological features of NPC.The aim of this paper is to study the impact of expression of LEF1 and TCF1(TCF7)in NPC,and assess whether LEF1 and TCF1(TCF7)can act as independent biomarkers for patients who are suffering from NPC.Methods:Paraffin embedded tissue blocks including 391 NPC,53 nasopharyngeal noncancerous ones and 28 pairs of primary tumors and metastases were randomly selected from tissue bank of pathology department,the Second Xiangya Hospital of Central South University.None of patients had received treatment before biopsy.The expression of LEF1 and TCF1(TCF7)proteins was detected by IHC in above tissues as well as positive and negative control groups.The expression of LEF1 and TCF1(TCF7)was analyzed by various advanced statistical methods in the difference between NPC VS nasopharyngeal noncancerous tissues and primary tumors VS metastases.And it was analyzed the relation of protein expression and clinicopathological features of NPC.The difference of P<0.05 was regarded statistically significant.Results:(1)There was a significant difference between NPC and nasopharyngeal noncancerous tissues in the expression of LEF1 and TCF1(TCF7)respectively and simultaneously(P<0.001,P<0.001,P<0.001).(2)Patients with positive expression of LEF1 were easier to have lymphatic metastasis(P=0.001),to get worse clinical stages(P< 0.001),and to have higher mortality(P<0.001).However,there was no significant difference in gender,age,histological types,lymphatic metastasis,clinical stages and survival status when it comes to TCF1(TCF7).(3)Patients with positive expression of LEF1 and TCF1(TCF7)simutaneously were easier to have lymphatic metastasis(P= 0.020),to get worse clinical stages(P=0.027),and to have higher mortality(P=0.004).(4)There was a significant difference between primary tumors and metastases of NPC in the expression of LEF1 and these two proteins simultaneously(P<0.001,P=0.003).(5)The further analysis of pair-wise association showed that the expression of LEF1 was positively associated with that of TCF1(TCF7)in NPC(r=0.103,P=0.030).(6)Kaplan-Meier survival curve analysis with log-rank significance test showed that the overall survival rate for NPC patients with positive expression of LEF1 and both two proteins was significantly lower(P<0.001,P=0.002),but there was no significant difference in TCF1(TCF7).(7)Multivariate Cox’s proportional hazard regression analysis indicated that the positive expression of LEF1 could act as an independent poor prognostic biomarker for NPC patients(P<0.001).Conclusions:1.There was a significant difference between NPC and nasopharyngeal noncancerous tissues in the expression of LEF1 and TCF1(TCF7)respectively and simultaneously.Also,positive association was detected between LEF1 and TCF1(TCF7)in NPC.These results suggested a synergistic effect of these proteins on the carcinogenesis in NPC.2.Compared with primary tumors,the expression of LEF1 and both two proteins in metastases of NPC was higher.What’s more,patients with positive expression of LEF1 and both two proteins were easier to have lymphatic metastasis,and their survival times were shorter.These results suggested that LEF1 and TCF1(TCF7)might accelerate the development of NPC.3.The expression of LEF1 might act as an independent prognostic biomarker for NPC patients.