Figure 1.

Selected microfluidic platforms for studying breast cancer tumor formation in ducts; normal epithelia lined by a basement membrane can proliferate locally to give rise to a tumor. Further transformation by epigenetic changes and genetic alterations leads to a carcinoma in situ, still outlined by an intact basement membrane. Three canonical surface receptors upregulated in tumor cells have been identified as distinguished biomarkers significant in cancer signaling: the estrogen receptor (ER), the progesterone receptor (PR), and the receptor tyrosine protein kinase ErbB-2, commonly known as HER2.