Results are presented as relative EGFR gene dosage levels in comparison to control (values in brackets). Values ≥ 5 were considered as EGFR amplification (A); values 1.5-5 were considered as low amplification level of EGFR (low A). Polysomy 7 (P) were examined based on GPER gene dosage status (details in Methods section). n.a. = non-analysed.