Table 4.

Prospective evaluation of the EGFR status of exons 19 and 21

% of tumoral	tumoral samples (n = 206)		EGFR mutations (n = 18)
cells	number	%	exon 19	exon 21	%
<20%	36	17.5	0	1	2.8
from 20 to 50%	98	47.6	3	6	9.2
>50%	72	35	5	3	11.1

Samples may contain at least 20% of tumor cells to allow a correct detection of mutations