Purpose Retinoid-binding protein (RBP7) is a member of the cellular retinol-binding protein (CRBP) family, which is involved in the pathogenesis of breast cancer (BRCA). The study aims to illustrate the prognostic value and the potential regulatory mechanisms of RBP7 expression in BRCA. Methods We utilized a series of bioinformatics tools, including HPA, GEPIA, UALCAN, ONCOMINE, Kaplan–Meier plotter, PROGeneV2, TISCH, LinkedOmics, UCSC Xena, MethSurv, SMART APP, bc-GenExMiner4.7, OSbrca, STRING, CARE, SwissDock and R software packages, to investigate the expression, prognostic value and functional regulatory networks of RBP7 in BRCA. Results Bioinformatics analysis with the TCGA and CPTAC databases revealed that the mRNA and protein expression levels of RBP7 in normal were higher compared to BRCA tissues. Survival analysis displayed that the lower expression of RBP7, the worse the prognosis in ER-positive (ER+) BRCA patients. Genomic analysis showed that promoter methylation result in transcriptional silencing of RBP7 in BRCA. Functional enrichment analysis demonstrated that downregulation of RBP7 expression may exert its biological influence on BRCA through the PPAR pathway and the PI3K/AKT pathway. Conclusions In summary, we identified RBP7 as a novel biomarker that is helpful for the prognosis of ER+ BRCA patients. Promoter methylation of RBP7 is involved in its gene silencing in BRCA, thus regulating the occurrence and development of ER+ BRCA through the PPAR and PI3K/AKT pathways.

Background: The activation of X-box binding protein 1 (XBP1) plays an essential role in the unfolded protein response (UPR) of the endoplasmic reticulum (ER). XBP1 is commonly expressed in various tumors and is closely related to tumorigenesis and progression. However, the role of XBP1 in lung adenocarcinoma (LUAD), especially the prognostic value of its alternative splicing isoforms, remains largely unknown.Methods: The LUAD datasets were retrieved from the The Cancer Genome Atlas, ArrayExpress and Gene Expression Omnibus. GEPIA2 and meta-analysis were employed to explore the prognostic value, and bioinformatics analysis with the TIMER2.0 database was used to investigate immune cell infiltration. We performed single-cell analyses to identify cell types with high XBP1 expression. In addition, polymerase chain reaction (PCR) and DNA sequencing were performed to verify the authenticity of the new spliceosome.Results: In this study, we found that high expression of XBP1 was significantly associated with a good prognosis, and XBP1 expression was significantly positively correlated with B cell infiltration in LUAD. In addition, we found that high-level expression of a novel splicing isoform, XBP1 (XBP1-003), improved the prognosis of LUAD. Protein structural analysis demonstrated that XBP1-003 has several specific protein domains that are different from those of other XBP1 isoforms, indicating a unique function of this isoform in LUAD.Conclusion: All these results suggest that XBP1 plays an antitumorigenic role in LUAD through alternative splicing, which may be related to the adaptation of plasma cells. This sheds new light on the potential strategy for LUAD prognosis evaluation and immunotherapy.

Retinoid-binding protein7 (RBP7) is a member of the cellular retinol-binding protein (CRBP) family, which is involved in the pathogenesis of breast cancer. The study aims to illustrate the prognostic value and the potential regulatory mechanisms of RBP7 expression in breast cancer. Bioinformatics analysis with the TCGA and CPTAC databases revealed that the mRNA and protein expression levels of RBP7 in normal were higher compared to breast cancer tissues. Survival analysis displayed that the lower expression of RBP7, the worse the prognosis in ER-positive (ER+) breast cancer patients. Genomic analysis showed that low expression of RBP7 correlates with its promoter hypermethylation in breast cancer. Functional enrichment analysis demonstrated that downregulation of RBP7 expression may exert its biological influence on breast cancer through the PPAR pathway and the PI3K/AKT pathway. In summary, we identified RBP7 as a novel biomarker that is helpful for the prognosis of ER+ breast cancer patients. Promoter methylation of RBP7 is involved in its gene silencing in breast cancer, thus regulating the occurrence and development of ER+ breast cancer through the PPAR and PI3K/AKT pathways.