PTGDR and non-small cell lung carcinoma: To determine the role of the miR-139-5p/RRM2 axis in AFAP1-AS1-mediated cell proliferation and chemotherapy resistance, NSCLC cells were transfected with scramble, siAFAP1-AS1, siAFAP1-AS1+NC, and siAFAP1-AS1+miR-139-5p inhibitor.