ARMS to detect NOTCH1 c.7544_7545delCT mutation. (A) Schematic diagram of the NOTCH1 gene (top) and protein (bottom), with its conserved functional domains (EGF-like repeats: LNR, LIN-12/NOTCH repeats; HD, heterodimerization; TM, transmembrane; Ankyrin repeats: TAD, transactivation domain; PEST, proline, glutamic acid, serine, threonine sequence). The TAD domain and the PEST sequence, both coded by exon 34, are magnified. Color-coded shapes indicate the position of the mutations found in the CLL training series (n = 34) and in the CLL validation series (n = 26). (B) Representative results of the ARMS assay showing 4 CLL samples that scored positive for the c.7544_7545delCT mutation (codes 5984, 5726, 11815, 3979) and 7 CLL samples that scored negative for the c.7544_7545delCT mutation (codes 4681, 5092, 3410, 8054, 7272, 11477, 5949). Negative samples show a normal band of 284 bp. Positive samples show an additional mutant band of 183 bp. Negative (C neg) and positive (C pos) controls also are included. Molecular weight (MW) is the 100-bp DNA ladder. Camera: Gel Doc 1000, BioRad; image acquisition software: Quantity One 4.5.0, BioRad. (C) Kaplan-Meier estimates of overall survival according to the results of the ARMS assay in the CLL training series (n = 309). Cases that scored negative by ARMS for the NOTCH1 c.7544_7545delCT mutation (ARMS neg) are represented by the blue line. Cases that scored positive by ARMS for the NOTCH1 c.7544_7545delCT mutation (ARMS pos) are represented by the red line.