Table 2. The effect of gefitinib on EGFR dimerization in A431 and SKOV3 cells.

A431
	Without pertuzumab		With pertuzumab
Effect of:	Without EGF	With EGF	Without EGF	With EGF
Gefitinib+complete medium	3.6±1.0*	1.9±0.1*	3.8±0.9*	1.6±0.2*
Gefitinib+serum free medium	3.6±0.8*	1.4±0.1*	3.0±0.6*	1.4±0.2

The intensity of the monomer and dimer Western blot bands were analyzed and compared within gels. The table presents EffectValues, i.e. quotients of dimerization degrees. Lysates within the same gel treated identically apart from the exposure of gefitinib (with/without FCS) were used as references. Data are presented as mean±S.E (n = 4).

*indicates treatments affecting dimerization, i.e. with a calculated effect significantly different from 1 (p<0.1). Gefitinib increases dimerization in A431 cells and in EGF treated SKOV3 cells, irrespective of FCS and pertuzumab.