miR‑455‑5p promotes cell invasion and migration in breast cancer.

MicroRNA (miR)‑455‑5p has been identified as a biomarker for various types of cancer and may therefore be involved in the regulation of cancer development and progression. However, the specific role and function of miR‑455‑5p in breast cancer remains unclear. The present study explored the expression levels and function of miR‑455‑5p in breast cancer. The results from reverse transcription‑quantitative polymerase chain reaction analysis revealed that miR‑455‑5p was significantly upregulated in breast cancer. Clinically, increased expression of miR‑455‑5p predicted a poor survival rate and miR‑455‑5p was identified as one of the independent prognostic factors for breast cancer patients. Furthermore, results from wound healing and Transwell assays revealed that miR‑455‑5p accelerated invasiveness and migration capabilities of breast cancer cells. In addition, programmed cell death 4 was identified as a downstream target of miR‑455‑5p and its expression was observed to be negatively regulated by miR‑455‑5p. Overall, miR‑455‑5p may function as an oncogene in breast cancer, and may therefore be used as a prognostic marker for breast cancer patients.