NRG1 and neoplasm: In contrast, only three out of 11 patients with HRDneg samples who experienced partial response, or complete response as best response had a concurrent pathogenic variant other than in TP53, and none of these variants (CCNE1 amplification, frameshift mutation in NRG1, and missense mutation in FGFR2) could explain the paradoxical radiologic tumor shrinkage.