PCa is the most prevalent cancer in men and as one of the malignant tumors of male genitourinary system, the biological behaviour of PCa is the most complex and the incidence is the higher in developed countries . In our country, the PCa incidence of upward trend is obvious in recent years. Based on the data of center for disease control and prevention of Shanghai for recent 20 years, the incidence of PCa sharp increased and the advanced metastasis PCa is currently incurable . For PCa, carcinogenesis and the mechanisms affecting the progression and prognosis are multistep processes . Although the previous reports have shown that many factors including lncRNA HCG11, miR-129, as well as TMPRSS2-ERG fusion gene have affected the development and prognosis of PCa [22–24], the prediction and diagnosis of PCa patients was still poor. Thus it is important to find a novel biomarker to improve the diagnostic efficiency of PCa.
Human SOX family has several members, and the functions of the gene family are various. For example, SOX genes regulate development and differentiation of many cell types. SOX genes within the same subgroup can counteract the function of the genes in another subgroup and the same SOX gene could regulate different stages of development in one cell type [25, 26]. SOX9 is a member of SOX family, which is a developmental transcription factor playing a key role in the regulation of sex determination, cartilage development, intestinal differentiation . At the 7.5 weeks of pregnancy, the expression of SOX9 can be found in embryonal tissue . In the existed studies, SOX9 acts as an important role in many tissues and organs . In recent years, researchers have found that as a transcription factor [29, 30], Abnormal expression of SOX9 is associated with the occurrence of many diseases, including many human cancers. For example, Guo et al. found that the expression of SOX9 was higher in HCC tissues than adjacent tissues and the overexpression of SOX9 in HCC tissues is of great predictive value on tumor progression and poor prognosis . Shao et al. found that the expression of SOX9 in gactric cancer was also higher than that in adjacent non-cancerous tissues. The expression of SOX9 was associated with the growth, invasion, and metastasis of gastric cancer, as well as the prognosis .
Moreover, SOX9 was also identified as one of the earliest molecular expressed in the primordial prostate. The conditional deletion of SOX9 demonstrated a requirement for SOX9 in ventral prostate differentiation and development. The study of Huang et al. reported that SOX9 expression played an important role in prostate development and the initiation of PCa . The study of Qin et al. showed that the combination of HIVEP3 and SOX9 help to predict the tumor progression and prognosis of PCa patients . However, the diagnostic value of SOX9 in PCa remains still unclear and is an active focus of our current research.
In our study, we found that the expression level of SOX9 was higher in PCa patients than that in healthy group. The similar result was in agreement with the previous studies. In addition, we also focused on the relationship between the expression level of SOX9 and the clinicalpathological features of PCa patients. The results showed that the expression level of SOX9 was significantly correlated with PSA, differentiation, and lymph node metastasis. And the result of ROC curves analysis indicated that the expression of SOX9 could be used as a diagnostic biomarker for PCa patients.