Leukemic recombinations involving heterochromatin in myeloproliferative disorders with t(1;9)
Sambani, Constantina × La Starza, Roberta Pierini, Valentina Vandenberghe, Peter Gonzales-Aguilera, Juan J Rigana, Helen Koumbi, Daphne Manola, Kalliopi N Stavropoulou, Chryssa Georgakakos, Vasileios N Pagoni, Maria Wlodarska, Iwona Mecucci, Cristina #
Cancer genetics and cytogenetics. vol:162 issue:1 pages:45-9
The unbalanced t(1;9) is a rare, recurrent rearrangement in polycythemia vera (PV) resulting in trisomy of both 1q and 9p arms, whereas a balanced t(1;9)(q12;q12), to our knowledge, has never been reported before. We studied two patients with PV and one with idiopathic myelofibrosis bearing an unbalanced t(1;9) and one patient with essential thrombocythemia with a balanced t(1;9). In all cases fluorescence in situ hybridization showed that the breakpoints were located within the satellite II family of heterochromatin of chromosome 1 and the satellite III of chromosome 9. Heterochromatin breakage and reunion produce the unbalanced t(1;9) and may contribute to a gene dosage effect due to gains of 1q and 9p. Case 4 with the balanced t(1;9), however, suggests that translocation of heterochromatin close to critical genes could interfere with their function. The molecular event underlying juxtaposition of satellite II of chromosome 1 and the satellite III of chromosome 9 remains to be elucidated.