Amplification of Wild-Type Represents a Novel Molecular Subtype of Several Cancer Types With Clinical Response to Selpercatinib.

PURPOSE

rearrangements and activating point mutations represent targetable genomic alterations in advanced solid tumors. However, the frequency and clinicopathologic characteristics of wild-type amplification in cancer and its potential role as a targetable oncogenic driver are not well-characterized.

METHODS

In two institutional cohorts of patients with solid cancers from the Dana-Farber Cancer Institute (DFCI) and Memorial Sloan Kettering Cancer Center (MSKCC) whose tumors underwent next-generation sequencing (NGS), the frequency and clinicopathologic features of wild-type amplification in the absence of rearrangements or activating mutations was assessed. The findings were validated using merged data from The Cancer Genome Atlas (TCGA), Genomics Evidence Neoplasia Information Exchange (GENIE), and China Pan-Cancer data sets.

RESULTS

The frequency of wild-type amplification across all solid cancers was 0.08% (26 of 32,505) in the DFCI cohort, 0.05% (26 of 53,152) in the MSKCC cohort, and 0.25% (71 of 28,623) in the cohort from TCGA, GENIE, and China Pan-Cancer. Cancer types with amplification included non-small-cell lung cancer (NSCLC), hepatobiliary cancer, prostate cancer, breast cancer, and others. The median copy number in -amplified cases was 7.5 (range, 6-36) in the DFCI cohort and 5.7 (range, 4-27.7) in the MSKCC cohort. Among 11 -amplified NSCLCs, eight had no other concurrent driver mutations. Finally, we report on a 69-year-old man with recurrent NSCLC harboring high-level wild-type amplification (22-28 copies) as the only identified putative genomic driver who experienced both a systemic and intracranial confirmed response to the RET inhibitor selpercatinib.

CONCLUSION

Amplification of wild-type represents a novel, targetable molecular subset of cancer.