| Disease | Lymphoid malignancies |
| Note | t(14;22)(q32;q11) analysed by G-banding has been reported in ALL, CLL/SLL, HCL, AML, NHL. Involvement of the genes IGH at 14q32 and IGL at 22q11 has been detected in one SLL and one DLBCL with t(14;22)(q32;q11). |
| Phenotype / cell stem origin | Small lymphocytic lymphoma (SLL): CD20+, CD23+, CD5+, CD10-, cyclinD1- Diffuse large B cell lymphoma (DLBCL): CD20+, BCL6+, CD10-, BCL2+ |
| Clinics | SLL: Cervical lymphadenopathy DLBCL: Generalized lymphadenopathy, night sweats, weight loss |
| Pathology | SLL: The lymph node showed diffuse infiltration with small lymphocytic cells with typical coarse clumped nuclear chromatin. Proliferation centers with paraimmunoblasts were present. DLBCL: Diffuse proliferation of large atypical lymphoid cells |
| Cytogenetics Morphological | The t(14;22)(q32;q11) was seen as the sole rearrangement in the SLL case. In the DLBCL case, there were several additional rearrangements. The complete karyotype of the latter was 52,XY,+Y,+der(3)t(3;9)(p11;p21),del(3)(q21),+7,+9,der(9)t(3;9)(q21;p21)x2,t(14;22)(q32;q11),der(15)t(1;15)(q21;p11),del(16)(p13),i(17)(q10),+18,+mar. The apparently identical translocation by G-banding has been seen in chronic myeloid leukaemia as well. However, this has been shown to be a three-way variant translocation of the classical t(9;22)(q34;q11) involving the genes ABL (9q34) and BCR (22q11). |
| Cytogenetics Molecular | Fluorescence in situ hybridization (FISH) analysis with locus-specific probes covering parts of IGH (PAC 998D24) and IGL (PAC 1019H10) showed fusion signals between the two probes. In the DLBCL case (figure to the left), two fusion signals were seen, indicating a reciprocal translocation between the two genes. In the SLL case (figure to the right), however, only the IGL probe was split and moved close to the IGH probe. The IGH probe remained seemingly intact on the der(14). To pinpoint more exact the breakpoint in IGL, three segments of the IGL probe were made using Long Range PCR. These segments were used as probes in further FISH analyses. In the SLL case, a split signal in the first segment probe was seen, locating the breakpoint between 12600bp and 37000bp from the centromeric end of the IGL probe. In the DLBCL case, a split signal in all the three segments was seen. One explanation might be that the IGL was duplicated and that one copy was moved to der(14). Another explanation might be that there was more than one breakpoint within IGL. |
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The left image shows FISH analysis on an interphase nuclei from the SLL case and the right image shows FISH analysis on a metaphase spread from the DLBCL case. The arrows point to the fusion signals of the IGH (PAC 988D24, 14q32) and IGL (PAC 1019H10, 22q11) probes. In the DLBCL case, a reciprocal translocation was seen where both IGH and IGL probes were split and juxtaposed. In the SLL case, however, only the IGL probe was split and moved to der(14). |
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