SCUBE3 Serves as an Independent Poor Prognostic Factor in Breast Cancer

Abstract

Background: Accumulating evidences indicate that the signal peptide-CUB-EGF-like domain-containing protein 3 (SCUBE3) plays a key role in the development and progression of many human cancers. However, the underlying mechanism and prognosis value of SCUBE3 in breast cancer are still unclear. Methods: The clinical data of 137 patients with breast cancer who underwent surgical resection in Taizhou Hospital of Zhejiang Province were retrospectively analyzed. We first conducted a comprehensive study on the expression pattern of SCUBE3 using the Tumor Immune Estimation Resource (TIMER) and UALCAN databases. In addition, the expression of SCUBE3 in breast tumor tissues was confirmed by immunohistochemistry. The protein-protein interaction analysis and functional enrichment analysis of SCUBE3 were analyzed using the STRING and Enrichr databases. Moreover, tissue microarray (TMA) was used to analyze the relationship between SCUBE3 expression levels and clinical-pathological parameters, such as histological type, grade, the status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2). We further supplemented and identified the above results using the UALCAN and bc-GenExMiner v4.4 databases from TCGA data. The correlation between the expression of SCUBE3 and survival was calculated by univariate Cox regression analysis to investigate whether SCUBE3 expression may be an independent prognostic factor of breast cancer. Results: We found that the expression level of SCUBE3 was significantly upregulated in breast cancer tissue compared with adjacent normal tissues. SCUBE3 expression was significantly correlated with ER (p = 0.018), PR (p = 0.015), HER2 (p = 0.039), and triple-negative status (p = 0.049) of patients with breast cancer. We further verified that the expression levels of SCUBE3 mRNA was significantly correlated with ER (p = 0.0007), PR (p = 0.0295), and triple-negative (p = 0.0024), respectively. There was no significant expression difference in the expression of SCUBE3 mRNA in age, HER2 receptor status, and nodal status (p > 0.05). In addition, the high expression of SCUBE3 was associated with relatively poor prognosis of ER- (p = 0.012), PR- (p = 0.029), HER2+ (p = 0.007). The univariate Cox regression analysis showed that the hazard ratio (HR) was 2.80 (95% CI: 1.20-6.51, p = 0.0168) in individuals with high SCUBE3 expression, and HR was increased by 1.86 (95% CI: 1.06-3.25, p = 0.0300) for per 1-point increase of SCUBE3 expression.Conclusions: These findings demonstrate that the high expression of SCUBE3 indicates poor prognosis in breast cancer. SCUBE3 expression may serve as a potential diagnostic indicator of breast cancer.