Aberrant regulation of cell growth pathways is required for normal cells to become cancerous, and in many types of cancer, cell growth is driven by a group of enzymes known as receptor tyrosine kinases (RTKs). The RTK epidermal growth factor receptor (EGFR) is overexpressed in over 30% of breast cancers; however, drugs that target RTKs, known as tyrosine kinase inhibitors (TKIs) have not been effective in treating breast cancer. Researchers believe that the cancer cells escape TKIs by circumventing the RTKs and utilizing other enzymes that are not TKI-sensitive.
