In our series, of the 22 cases analyzed with both NRG1 FISH (positivity criterion of at least 15% of tumor nuclei with a split between the 5′- and the 3′- parts of the probes and/or isolated single 3′-NRG1 signal) and RNAseq, 17 cases were FISH– RNAseq– and 5 cases were FISH+ RNAseq+ (no FISH+ RNAseq– or FISH– RNAseq+ cases in our study) resulting in 100% sensibility and specificity for the NRG1 FISH test. Here, NRG1 is linked to neoplasm.