Tumor-associated macrophages are related to metastasis and malignancy so the co-culture of tumor-associated macrophages with cancer cells of MCF7 and MDA- MB231 cell lines is accompanied by a higher percentage of CSC content and higher expression of HIF-1α, Twist1, β- catenin and NF-Κβ transcriptional factors. The gene discussed is TWIST1; the disease is neoplasm.