sample1_EGFR_19 53  exon19 ...
sample1_EGFR_19 12      exon20 ...
sample2_EGFR_19 20      exon19 ...
sample3_EGFR_20 65      exon20 ...
sample2_EGFR_19 25      exon12 ...
sample1_EGFR_20 12      exon20 ...
sample3_EGFR_20 125 exon20 ...