Correct localization of the probes used for the detection of t(9;14)(p13;q32) and t(11;18)(q21;q21).

(A) Localization of the PAX-5–specific probe to chromosome 9 at band p13 (red). The green signal is that of chromosome 4 centromeric probe. (B) Normal pattern of hybridization for the IgH/PAX-5 probes, consistent with 2 pairs of discrete green and red signals, respectively, without fusion signals. (C) Metaphase FISH assay in a patient with known t(9;14)(p13;q32) serving as the positive control. Metaphase shows 2 fusion signals indicating a balanced reciprocal translocation and the germ line configuration for the IgH probes (green) and the 9p13 PAX-5probe (red). Smaller boxes in the lower left corner depict an enlarged view of the der(14)t(9;14) chromosome, showing the fusion signal indicative of the translocation (right small box) and the same chromosome after stripping of the probes and hybridizing with whole chromosome paints (WCPs). Left small box: red indicates WCP 14, and green indicates WCP 9. (D) Interphase FISH results on the same patient, and 2 distinct fusion signals indicative of the balanced translocation. (E) Correct localization of the probes used for the detection of t(11;18)(q21;q21). (F) Normal interphase FISH pattern for these same 2 probes, again consistent with 2 pairs of discrete green and red signals, respectively, without resultant fusion signals.