HIF1A and breast carcinoma: Moreover, another recent study of Wang J. and colleagues demonstrated that circPVT1 which resulted upregulated in breast cancer, exerts a sponge activity on miR-29a-3p leading to the upregulation of AGR2 (Anterior gradient protein 2) that in turns enhance HIF-1α expression accelerating cell proliferation, migration and invasion abilities of breast cancer cells [70].