Objective: To investigate the expression of RNA binding motif protein 7 (RBM7) in human breast cancer cell MDA-MB-231, and its effects on the expression of A kinase anchor protein 12 (AKAP12). Methods: MDA-MB-231 cells were respectively transfected with RBM7 overexpressing, knocking down lentivirus (experimental group) and corresponding control lentivirus (control group). Stable transfected cell lines were selected with puromycin and verified via fluorescence microscopy. Quantitative real time polymerase chain reaction (qRT-PCR) and Western blot assays were used to verify the expression of RBM7, and to investigate the effects of altered RBM7 expression on the expression of AKAP12. Gene Ontology (GO) enrichment analysis was performed on the differentially expressed genes obtained by RNA sequencing, and revealed significantly enriched pathways regulated by RBM7. At the same time, the UALCAN database was employed to assess AKAP12 expression in breast cancer. The relationship between RBM7 and AKAP12 was studied by RNA binding protein immunoprecipitation (RIP) assays. Furthermore, immunohistochemical analysis was performed to delineate the relationship between RBM7 and AKAP12 in breast cancer tissues. Results: RBM7 overexpression and knockdown lentiviruses were transfected in the breast cancer cell MDA-MB-231, respectively. Stable cell lines with RBM7 overexpression and knockdown were successfully established, within two weeks of puromycin selection. GO enrichment analysis of differentially expressed genes obtained by RNA-sequence revealed that RBM7-regulated genes were mainly enriched in the cell cycle pathway. Moreover, the UALCAN database analysis revealed that AKAP12 was lowly expressed in breast cancer (p<0.05). It was observed that overexpression of RBM7 could downregulate RNA and protein expression of AKAP12, and knockdown of RBM7 upregulated RNA and protein expression of AKAP12 via qRT-PCR and Western blot (p<0.05). RNA-binding protein immunoprecipitation (RIP) assays revealed that RBM7 could directly bind to mRNA of AKAP12 (p<0.05). Immunohistochemical analysis revealed an inverse correlation between RBM7 and AKAP12 expression in breast cancer tissues (p<0.05). Conclusion: RBM7 downregulated the expression of AKAP12 in breast cancer cell MDA-MB-231 and breast cancer tissues.