Detection of genomic abnormalities by interphase fluorescence in situ hybridization in multiple myeloma

Objective To investigate the clinical significance of I-FISH for detection of genomic abnormalities in MM. Methods Twenty newly diagnosed MM patients(seven cases at stage Ⅰ , five cases at stage Ⅱ and eight cases at stage Ⅲ according to Bataille staging) were analyzed by combining the technique of CC (R-binding stain) and I-FISH [ including GLP13q14 (RBI gene), GLP17p13. 1 (P53 gene),GLP13q14. 3(D13S319) ,GLP1q21 ,GLP14q32(IgH gene) DNA sequence probes]. These two methods were compared for the detection rates of chromosomal and genomic abnormalities in MM and the association between genomic abnormalities and Bataille stages was also analyzed. Results CC examination showed only 1 case [5% (1/20) ] was found complex chromosomal abnormalities--46,XX,-2,del(3) (p21) ,add(6)(q26) ,der(10)(q26),der(14)(q32), + mar, inc[6]. While I-FISH assay showed that 12 cases [60%(12/20) ] were found genomic abnormalities. The frequencies of RB1, D13S319 and P53 were all 30%(6/20), and the frequencies of IgH gene and 1q21 were both 20% (4/20). The detection rate of the I-FISH was much higher than CC (χ2 = 9. 09, P = 0. 001) according to paired χ2 test. Of 20 patients,6 cases had RB1 gene abnormality, 1 case at stage Ⅰ , 2 cases at stage Ⅱ and 4 cases at stage Ⅲ. Of 20 patients, 6 cases had D13S319 gene abnormality, 2 cases at stage Ⅰ , 1 case at stage Ⅱ and 3 cases at stage Ⅲ. Of 20 patients, 6 cases in 20 had P53 gene abnormality, 2 cases at stage Ⅰ and 4 cases at stage Ⅲ. Of 20 patients, 4 cases had 1q21 gene abnormality, 2 cases at stage Ⅰ and 2 cases at stage Ⅲ. Of 20 patients, 4 cases had IGH gene abnormality, 1 case at stage Ⅰ and 3 cases at stage Ⅲ. Conclusion Ⅰ-FISH has higher detection rate for the genomic abnormalities in MM and can be used in detection of MM patients in different Bataille stages. Key words: Multiple myeloma; In situ hybridization,fluorescence; Cytogenetic analysis