Fig. 6. Characterization of possible types of JT1q12 chromosome instability.

Depiction of normal chromosome 1 (yellow), centromere (black), 1q12 (red), and 1q21 (green) (a). Two transient aberrations of 1q12 are precursors to subsequent clonal aberrations, the first being 1q12 decondensation and breakage (b), which leads to the formation of 1q12 triradials (c). The extra copy of 1q generated by the triradial of 1q12 can result in multiple types of unbalanced CNAs. A JT1q12 to 17p can result in the concomitant gain of both 1q12 and 1q21 and deletion of 17p (TP53) (d). Extra copies of 1q12 that do not successfully jump to an RC result in acentric lagging copies of 1q and subsequent micronuclei (e). A JT1q12 to 8q (f) demonstrates ongoing instability including the two sublcones. Subclone 1 involved the loss of 1q from 8q, resulting in a sister chromatid fusion (SCF) (arrow) at 1q12 (g). Subsequent formation of dicentric 8 and a 1q12 bridge (h) is an intermediate step in BFB cycles resulting in the amp of MYC and 16pter (i). In subclone 2, 1q12 instability is demonstrated by a triradial of 1q on 8q resulting in the generation of additional copies of 1q21 (j). The additional copies of MYC, 16p, 1q12, and 1q21 are subsequently translocated to a normal chromosome 1q resulting in an insertion (k). A JT1q12 to 7q (l) subsequently results in insertion of MET into multiple nonhomologous chromosomes, including both 6q, causing a near arm-length deletion in 6q (m), and also to an RC 1q resulting in insertion of MET into a normal chromosome 1 (n)