Variant Philadelphia Chromosome Identified by Interphase Fluorescence In Situ Hybridization (FISH) without Evidence on G-banded Karyotyping and Metaphase FISH

Mi Kyung Kim, Yeung Chul Mun, Chu Myong Seong, Wha Soon Chung, Jungwon Huh
2010 The Korean Journal of Laboratory Medicine  
A variant Philadelphia chromosome (Ph) is generated from translocation of one or more partner chromosomes in addition to chromosomes 9 and 22. We have described the cases of 2 patients bearing variant Ph detected by interphase FISH but not detected by G-banded karyotyping and metaphase FISH. FISH was performed using BCR/ABL dual color dual fusion translocation probes (Abbott Molecular, USA). A 52-year-old man was diagnosed with acute leukemia of mixed phenotype. G-banded karyotyping showed
more » ... ,t(9;22)(q34;q11.2)[12]/47,idem,+der (22)t(9;22) [5]/46,XY[3]. Interphase FISH revealed nuc ish(ABL1,BCR)×3(ABL1 con BCR×2)[329/450]/(ABL1,BCR)× 4(ABL1 con BCR×3)[5/450]/(AL1,BCR)×3(ABL1 con BCR×1)[44/450]. Metaphase FISH showed ish (9;22)(ABL1+,BCR1+;BCR+,ABL+)[22]/der(22)(BCR+,ABL1+)[3]. The other case was that of a 31-yr-old male patient diagnosed with CML in the blastic phase. G-banded karyotyping of all 20 metaphase cells showed 47,XYYc,dup(1)(q21q32),del(7)(p11.2),t(9;22)(q34;q11.2). Interphase FISH revealed nuc ish(ABL1,BCR)×3(ABL1 con BCR×2)[254/600]/(ABL1,BCR)×3(ABL1 con BCR×1)[191/600]. Metaphase FISH showed ish t(9;22)(ABL1+,BCR+;BCR+,ABL1+)[16]. These results suggest that typical t(9;22) and variant Ph may coexist in the same patient, and interphase FISH may facilitate the detection of the variant Ph that cannot be detected by G-banded karyotyping alone. (Korean J Lab Med 2010;30:711-7)
doi:10.3343/kjlm.2010.30.6.711 pmid:21157160 fatcat:5p5d2325f5hnniqoj3uwb5e2hq