Increased expression of SYCP2 predicts poor prognosis in patients suffering from breast carcinoma.

Overexpression of synaptonemal complex protein-2 ( SYCP2 ) has been identified in various human papillomavirus (HPV)-related carcinomas, whereas its significant role in breast carcinoma remains unclear. The aim of this study was to elucidate the prognostic value and potential function of SYCP2 in breast carcinoma. Herein, data for breast carcinoma patients from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas database (TCGA) were analyzed. The enrichment analysis of SYCP2 including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Friends, and GSEA was performed. Kaplan-Meier analysis, Cox regression, and receiver operating characteristic (ROC) curves were employed for determining the predictive value of SYCP2 on clinical outcomes in patients suffering from breast carcinoma. A nomogram was generated to predict the effect arising from SYCP2 on prognosis. The association analysis of SYCP2 gene expression and diverse immune infiltration levels was conducted through ssGSEA and ESTIMATE analysis, which consisted of dendritic cell (DC), neutrophil, eosinophil, macrophage, mast cell, NK cell, and other 18 cell subtypes. The results showed that SYCP2 expression was significantly elevated in breast carcinoma tissues as compared with that of normal tissues ( p < 0.001). SYCP2 plays a certain role in pathways related to DNA methylation, keratinocyte differentiation, steroid hormone biosynthesis, and immune infiltration. The high expression of SYCP2 had a significant relationship to age, pathological type, ER expression, and PR expression ( p < 0.001). Kaplan-Meier survival analysis showed that patients suffering from breast carcinoma characterized by high- SYCP2 expression had a poorer prognosis than patients with low- SYCP2 expression ( p = 0.005). Univariate and multivariate Cox regression analyses revealed that SYCP2 had an independent relationship to overall survival ( p = 0.049). Moreover, ROC curves suggested the significant diagnostic ability of SYCP2 for breast carcinoma, and as time went on, SYCP2 had more accurate prognostic efficacy. Furthermore, a high level of SYCP2 expression was found to have a relationship to poor prognosis of breast carcinoma in the subgroups of T3, N0, and M0, and infiltrating ductal carcinoma (HR > 1, p < 0.05). The calibration plot of the nomogram indicated that the SYCP2 model has an effective predictive performance for breast carcinoma patients. Conclusively, SYCP2 plays a vital role in the pathogenesis and progression of human breast carcinoma, so it may serve as a promising prognostic molecular marker of poor survival.