Searching for activating ERBB2 mutations with a high throughput screen

There are numerous reports of ERBB mutations in various cancer types. Majority of the identified cancer-associated mutations usually accumulate in certain functional areas of these genes, called hotspots, and the frequency of these hotspot mutations in the affected individuals is usually relatively high. Mutations outside of these hotspot regions are infrequent. Although, most of them are likely passenger mutations, recent evidence shows that some of these infrequent mutations are activating in nature. In this study, the aim was to identify activating ERBB2 mutations and assess their sensitivity to tyrosine kinase inhibitors and anti-ERBB2 therapeutic antibody trastuzumab. A library of randomly mutated ERBB2 cDNA variants was created and the aim was to discern activating mutations from this library using a functional assay that allows enrichment of gain-of-function mutations. In addition to identification of two previously characterized activating ERBB2 mutations G660D and V777L, a potentially interesting variant of unknown functional significance conferring resistance to trastuzumab, ERBB2 D638G, was discovered