Fig. 2: Metaphase cells from patients demonstrating different types of progression events involving isochromosomes 1q.
From: An acquired high-risk chromosome instability phenotype in multiple myeloma: Jumping 1q Syndrome
Top patient no 7 (a–d) showing progressive gains of both 1q12 and 1q21 resulting from BFB cycle amplifications of the 1q12–1q21 region. The 1q12 breakpoints generate gains of 1q21 in extended ladder-like pattern. FISH probes 1q12(red) and 1q21 (green). Normal chromosomes 1 from these cells (a–d) not shown. a An isochromosome 1q showing an alternating pattern of 1q12 and 1q21 with four copies of each (arrows). b Increased copy number amplification of both 1q21 and 1q12 resulting in six copies of both 1q12 and 1q21 in this chromosome. c The iso(1q) in this cell shows the characteristic alternating copies of 1q12 and 1q21 and extended ladder-like structure seen in BFB cycles demonstrating eight copies of both 1q12 and 1q21. d A cell with a total of ten copies of both 1q12 and 1q21 with six copies on the iso(1q) and four small extra-chromosomal acentric rings each with single copies of 1q12 and 1q21. Bottom Partial karyotypes from patient no 4 demonstrating two isochromosome 1qs with intra-arm heterogeneity of both CNAs and loci position of 1q12 and 1q21. FISH probes 1q12 (red) and 1q21 (green). a This cell shows the expected copy number and loci position for two “normal” isochromosomes 1q with four copies of 1q12 and 1q21. b The iso(1q) on left shows normal copy number and positions for 1q12 and 1q21, while the iso(1q) on the right shows the 1q21 locus has inverted distally in both arms. c The iso(1q) on left shows the normal copy number and positions for 1q12 and 1q21; however, the iso(1q) on right shows four copies of 1q12 and three copies 1q21 (arrows) with unequal CNAs between the arms. d Both iso(1q)s show intra-arm changes, the iso(1q) on left shows two copies of 1q12 and three copies of 1q21, while the iso(1q) on the right shows a large focal amplification of 1q12. The copy number of 1q21 in this cell is five. e A cell showing eight copies of 1q12 (arrows) and seven copies of 1q21 distributed among three chromosomes. Left, iso(1q) with three copies 1q12 and two copies of 1q21. Center, iso(1q) with four copies of both 1q12 and 1q21 displaced distally of normal positions. Right single copies of 1q12 and 1q21 on a der(16)
