[Detection of deletion of the long arm of chromosome 13 and translocation of immunoglobulin heavy chain gene by interphase fluorescence in situ hybridization in patients with multiple myeloma].

Objective: To investigate the clinical significance of the deletion of the long arm of chromosome 13 [del (13 q) ] and translocation of immunoglobulin heavy chain gene [t (14 q) I in multiple myeloma (MM) patients.

Methods: Myeloma cells were isolated from hone marrow by direct immunomagnetic cell sorting and interphase fluorescence in situ hybridization (FISH) was performed in 24 MM patients to detect del (l3q) and t (l4q).

Results: The positive rates of del (l3q) and t (l4q) were 45.83% and 37.50% respectively. Five patients (20.83%) had both two abnormalities and 15 patients (62.50%) had at least one abnormality. Univariate analysis showed that the positive rates of del (l3q) were 35.71% and 66.67% in responders and non-responders (P = 0.214) and the positive rates of t (l4q) were 21.43% and 66. 67% in responders and non-responders (P = 0.077). Multivariate analysis showed that del (13q) (OR = 5.761, 95% CI 0.500-66.391, P = 0.160), t (14q) (OR = 6.576, 95% CI 0.580-74.614, P = 0.129), and corrected serum calcium level (OR = 8.080, 95% CI 0.738-88.427, P = 0.087) were relatively independent negative factors for response to therapy, with the corrected serum calcium level being the strongest reversely-correlated factor.

Conclusions: Interphase FISH is a sensitive method to investigate the cytogenetics of MM. Del (13q), t (14q), and corrected serum calcium level can be used to predict treatment response and prognosis.