Tarceva belongs to a group of cancer drugs known as epidermal growth factor receptor (EGFR) inhibitors.

Epidermal growth factor is a protein present in the body. Structures called epidermal growth factor receptors (EGFRs) sit on the surface of many types of cancer cells. The receptors allow epidermal growth factor to attach to them. When these growth factors attatch to the receptors, a protein called tyrosine kinase (TK) triggers chemical signals to make the cell grow and divide.

Tarceva works by attaching itself to the tyrosine kinase protein. It prevents the chemical signals from being produced. This may stop the cells dividing and Tarceva therefore may be able to stop the cancer cells from growing.

Tests may be done to check the level of EGFR. These will tell if you are likely to benefit from Tarceva. Testing can be done at the same time as diagnosis, or samples of cancer cells from previous biopsies or surgery may be used.