EGFR and dermatological toxicity: Present results also show a tendency for an association between intron 1 EGFR polymorphism and cetuximab-related skin toxicity: the incidence of grade 2-3 toxicity was 1.5-fold greater in patients bearing short CA-repeats in intron 1 of EGFR gene (CA sum ≤ 35) as compared to others (p = 0.058, Figure 1).