Analysis of bone marrow cells.

(A) Representative cells from a myeloma bone marrow as analyzed by TRI-FISH. A normal plasma cell (blue cytoplasm) is surrounded by several nonplasma cells. Note that all nuclei contain 2 red and 2 green signals. The green signal is derived from the chromosome 10 reference probe and the red signal originates from the chromosome 13 probe D13S272. (B) TRI-FISH indicates interstitial deletion of D13S272. Cells from case 26 were hybridized with (i) D13S1150, (ii) D13S272, and (iii) AFMA301wB5 probes (red) and the chromosome 10 probe (green). Note the loss of signal for D13S272 (ii), which occurred in 22% of the light chain-restricted plasma cells. Loss of signal was not observed for the other markers. (C) Clonal heterogeneity and dispersed interstitial deletions in myeloma. Bone marrow cells from case 50 were simultaneously hybridized with probes for D13S272 (red) and D13S31 (green). Approximately 5% of the cells were normal (i), 48% of the cells demonstrated monosomy (ii), 12% of the cells showed monosomy for D13S272 and complete loss of the D13S31 signal (iii), and 23% of the cells had no signal for either probe (iv).