Significantly more isolated BM in EGFR negative patients was also found in the study of Eichler et al., 31% vs. 7% (p = 0.03).25 On the contrary, Lee et al. found a higher incidence of isolated BM in EGFR mutated patients from a series of 117 resected tumours (24% vs. 9%), which, however, was not statistically significant.21 This finding indicates a different biology of the disease. This evidence concerns the gene EGFR and neoplasm.