The breakpoint region of the most common isochromosome, i(17q), in human neoplasia is characterized by a complex genomic architecture with large, palindromic, low-copy repeats.

Although a great deal of information has accumulated regarding the mechanisms underlying constitutional DNA rearrangements associated with inherited disorders, virtually nothing is known about the molecular processes involved in acquired neoplasia-associated chromosomal rearrangements. Isochromosome 17q, or "i(17q)," is one of the most common structural abnormalities observed in human neoplasms. We previously identified a breakpoint cluster region for i(17q) formation in 17p11.

A novel gene, MSI2, encoding a putative RNA-binding protein is recurrently rearranged at disease progression of chronic myeloid leukemia and forms a fusion gene with HOXA9 as a result of the cryptic t(7;17)(p15;q23).

The pathogenetic role of the P210 BCR/ABL1 fusion gene in the chronic phase of chronic myeloid leukemia (CML) has been well established.In contrast, the genetic mechanisms underlying the disease progression into the accelerated phase (AP) and the final blast crisis (BC) remain poorly understood. We have previously identified (A.

Multicolor COBRA-FISH analysis of chronic myeloid leukemia reveals novel cryptic balanced translocations during disease progression.

During the initial indolent chronic phase of chronic myeloid leukemia (CML), the t(9;22)(q34;q11), resulting in the Philadelphia chromosome (Ph), is usually the sole cytogenetic anomaly, but as the disease progresses into the accelerated phase (AP), and eventually into aggressive blast crisis (BC), secondary aberrations, mainly unbalanced changes such as +8, i(17q), and +Ph, are frequent. To date, molecular genetic studies of CML BC have mainly focused on alterations of well-known tumor-suppressor genes (e.g.