In silico bioinformatics analysis further confirms that miRNA functions in hypoxia are regulated by COX-2/EP4/PI3K/Akt pathways and that miRNA has a negative correlation with transcription factors that regulate the expression of NFκB1 and PTEN. In human breast tumors, HIF-1α expression is significantly high and we estimated the highest expression in the ER-positive, PR-positive, and HER2-negative breast tumors. The gene discussed is ESR1; the disease is breast neoplasm.