PTPN1 and breast carcinoma: Also, several catechins present in green tea leaves decreased the viability of MCF-7 breast cancer cells and were identified as PTP1B inhibitors, namely: epigallocatechin (IC50 = 103.8 ± 10.1 μM), epigallocatechin gallate (IC50 > 500 μM), epicatechin (IC50 > 500 μM), and epicatechin gallate (IC50 > 500 μM) [85].