EVIDENCE FOR SOMATIC PAIRING OF CHROMOSOME-7 AND CHROMOSOME-10 HOMOLOGS IN A FOLLICULAR LYMPHOMA

Fluorescence in situ hybridization using centromeric probes for chromo somes 7 and 10 in a follicular lymphoma revealed only one signal in ab out 40% of interphases, whereas two copies of each chromosome were con sistently seen in metaphases. In four out of 18 metaphases both copies of chromosome 7 were situated close to one another. In contrast, two signals for chromosome 1 were seen in 94% of interphases, consistent w ith observations on metaphases. The findings suggest chromosome-specif ic somatic pairing, the functional significance of which is at present unknown, and reinforce previous evidence suggesting that care should be taken in the interpretation if interphase signal numbers using cent romeric probes in neoplastic as well as normal material.