Oral squamous cell carcinoma (OSCC) is an aggressive human malignancy worldwide. Despite advances in prevention and treatment, the five-year survival rate of OSCC patients remains low due to metastasis and local recurrence [8, 20]. Tumor progression and prognosis evaluations are a great challenge for OSCC patients in clinic, due to the lack of effective and reliable biomarkers. Growing evidences have demonstrated that genetic factors play a pivotal role in progression of OSCC. Therefore, to investigate the OSCC-related genes may explore novel and effective biomarkers for patients with OSCC. In the present study, we investigated the prognostic value of KLF7 in OSCC patients.
KLFs are a family of zinc-finger transcription factors, which are widely expressed in multiple human organs or tissues . KLF family is involved in diverse biological processes, and their abnormal expression may lead to human diseases, like cancer . In oral cancer, several members of the KLFs family had been proved to be implicated in the pathogenesis of the cancers. For examples, Uchida D et al. had demonstrated that knockdown the expression of KLF2 would achieve the anti-tumor effects in oral cancer cells . KLF4 and KLF5 might regulate the dedifferentiation and differentiation of oral carcinoma cells, thus leading to oral cancer carcinogenesis [24–26]. KLF8 was up-regulated in oral cancer cells, and its down-regulation might suppress the proliferation and clone formation of the cells . In addition, the cellular levels of KLF13 was significantly correlated with proliferation ability and therapy sensitivity of oral cancer, which might be a potential diagnostic biomarker and therapeutic target for oral cancer . However, to our knowledge, the function of KLF7 as well as its clinical significance had been rarely reported in OSCC.
In the present study, we found that KLF7 expression levels were up-regulated in OSCC tissues compared with adjacent non-tumor tissues. Additionally, the expression of KLF7 was positively correlated with tumor size, TNM stage, smoking status and drinking status. This data indicated that KLF7 might be involved in the development of OSCC. High expression of KLF7 predicted malignant clinical characteristics for the patients with OSCC. The study scheduled by Ding et al. have demonstrated that over-expression of KLF7 via mediating the expression of snail enhanced the migratory potential of OSCC cells, and induced epithelial-mesenchymal transition (EMT) and lymph node metastasis . However, the carcinogenic mechanisms of KLF7 in OSCC was not investigated in the current study. Further relevant researches were still needed to address the issues.
Given its functional roles in OSCC development, we investigated the clinical performance of KLF7 in prognosis evaluation in OSCC population. Kaplan-Meier survival analysis with log-rank test suggested that high-expression group had obviously shorter overall survival than the low-expression group. Multivariate analysis with a Cox proportional hazards model indicated that high KLF7 expression was independently linked to poor survival of patients with OSCC. KLF7 might serve as an independent prognostic factor for patients with OSCC. Although we confirmed the prognostic value of KLF7 in OSCC, there were several limitations in our study. First, the sample size was relatively small. Second, only one single population was enrolled in our researches. Due to the diverse genetic background, the expression profile of KLF7 in other races might be different. In addition, despite of the diverse biomarkers confirmed for OSCC, few of then were applied in clinic. Thus, subsequent investigations still required to analyze the clinical application of KLF7 for OSCC cases.