Table 1.

Association of EGFR expression with response status to gefitinib

Methods of evaluation of EGFR expressionStatistics describedResponse
PD/SDCR/PRPa
Specific antibodies for the ED of EGFR
ED IHC membraneN (missing)52 (0)15 (0)0.2717b
Mean33.9472.00
SEM7.92432.40
ED IHC membrane and cytoplasmN (missing)52 (0)15 (0)0.2665b
Mean42.8876.00
SEM8.3927.51
ED AQUAN (missing)51 (1)15 (0)0.0581
Mean8.268.90
SEM0.150.34
Specific antibody for the internal domain of EGFR
ID IHC membraneN (missing)52 (0)15 (0)0.0063
Mean184.6257.3
SEM12.1422.94
ID IHC membrane and cytoplasmN (missing)52 (0)15 (0)0.0026
Mean178.8245.3
SEM10.3516.38
ID AQUAN (missing)50 (1)13 (2)0.0017
Mean11.2212.68
SEM0.210.35

NOTE: To compare the performance of the techniques/antibodies to discriminate between responders and nonresponders, this table displays the results with the 70 patients on which the 6 different evaluations were carried out.

  • aIndependent, 2-sample t test for difference in mean score between responders and nonresponders. Equivalence of variance was tested.

  • bIn case of inequality of variance, a t test not assuming equality of variances was used.