Sensitivity of Multiple Color Spectral Karyotyping in Detecting Small Interchromosomal Rearrangements

Abstract

Multiple color spectral karyotyping (SKY) has been proven to be a very useful tool for characterization of the complex rearrangements in cancer cells and the de novo constitutional structural abnormalities. The sensitivity of SKY in detecting interchromosomal alterations was assessed with 10 constitutional translocations involving subtelomeric regions. Among the 13 small segments tested, 9 were clearly visualized and 8 were unambiguously identified by SKY. Fluorescence in situ hybridizations (FISH) with subtelomeric probes confirmed the reciprocity in three of the four translocations in which a small segment was not detectable by SKY. On the basis of resolution level of G-banding and the information obtained from the FISH analysis, the minimum alteration that SKY can detect is estimated to be 1,000-2,000 kbp in size with the currently available probes. This study has demonstrated the power, but also the limitations, of SKY in detecting small interchromosomal alterations, particularly those in subtelomeric regions.

Spectral karyotype analysis of colon cancer cell lines of the tumor suppressor and mutator pathway

“…Although we can not rule out the possibility of very small translocated segments, their existence seems to be unlikely because of the high sensitivity of the SKY method. Fan et al (2000) described the lower limit for detection of chromosomal imbalance in the order of 1-2 Mb. Not much is known about the reasons for the striking cytogenetic differences in MSI and MSS colon cancer cells.…”

Detection of submicroscopic aberrations in patients with unexplained mental retardation by fluorescence in situ hybridization using multiple subtelomeric probes

“…Spectral karyotyping (SKY) was performed as previously described 26 for the patient and the parents when a rearrangement was detected by FISH using the Multiprobe-T system.…”

“…26 In the current study, we also performed SKY analysis for the four cases with unbalanced rearrangements. In each case, SKY was successfully used to visualize the submicroscopic rearrangement, as well as the full cryptic translocation in the parent when available for analysis.…”

Array CGH in Fetal Medicine Diagnosis

“…Several other techniques have emerged based on the original method of FISH. Using the techniques of multicolor FISH (M-FISH) and spectral karyotyping (Spectral karyotyping -SKY), each chromosome takes a "signature" spectrum, enabling the identification of complex rearrangements involving more than two chromosomes, as well as the source and content of marker chromosomes (Haddad et al, 1998, Fan et al, 2000, with a resolution of 1Mb to 5Mb for the M-FISH (Speicher et al, 1996) and 1Mb to 2 Mb for SKY (Schröck et al, 1997).…”