To assess if metastable hairpin-loop structures could be associated with pG4 sequences that represent the top hotspots of mutations in the germline (pG4_HGMD1 in exon 2 of MEN1) or in cancer (pG4_COSMIC1 in exon 20 of NOTCH1), we first mapped on the ΔG histogram the 500-bp bins in which these pG4 sequences were embedded. This evidence concerns the gene NOTCH1 and cancer.