Urothelial cancer harbours EGFR EGFR and HER2 HER2 amplifications and exon 20 insertions

摘要

Objective To review the genomic landscape of advanced urothelial carcinoma (UC) to assess the frequencies of EGFR and ERBB2 ( HER2 ) alterations. Materials and Methods Tumour specimens from 3753 patients with advanced UC were assayed with hybrid capture‐based comprehensive genomic profiling of 180–395 genes. Tumour mutational burden (TMB) was assessed on 0.8 or 1.1?Mb of DNA, and is reported as mutations per megabase. Results In 3753 cases of UC, EGFR alterations were detected in 4.1% (154) and were most commonly amplifications (64%; 99/154), while exon 20 insertions ( EGFR exon20ins ) were the second most common alteration (18%; 27/154). Alterations in ERBB2 were observed in 15% (552/3753) of cases and, similarly, ERBB2 amplification was the most commonly observed alteration (278/552; 50%); ERBB2 exon20ins occurred in 3.6% (20/552) of cases. EGFR exon20ins and ERBB2 exon20ins occurred in younger patients (median age 62 vs 69?years, P = 2.6E‐2 and 60 vs 68?years, P = 7.8E‐4), and these cases had significantly lower TMB (median 3.6 vs 7.2, P = 2.7E‐4 and 2.5 vs 10, P = 1.2E‐7) and less frequent TP53 alterations (3.7% vs 83%, P = 4.3E‐14 and 20% vs 68%, P = 9.8E‐4) compared to cases with other EGFR or ERBB2 alterations. Conclusion EGFR and ERBB2 alterations occur in 4% and 15% of UC, respectively. EGFR exon20ins and ERBB2 exon20ins were present in 0.7% and 0.5% of UC overall and collectively define a small, but distinct, subset of UC with infrequent co‐occurrence of other drivers and low TMB. Given recent promising clinical studies of inhibitors with activity against exon 20 insertions in non‐small cell lung cancer, consideration should be given to developing a trial inclusive of patients with UC harbouring these alterations.