Abstract: Ｏｂｊｅｃｔｉｖｅ：To identify the molecular genetic characteristics of bone marrow plasma cells in patients with systemic light chain amyloidosis,and explore the correlation between abnormal cytogenetics and clinical characteristics and as well as that between abnormal cytogenetics and plasma cell phenotype.Ｍｅｔｈｏｄｏｌｏｇｙ：Interphase florescence in situ hybridization (iFISH) was used to detect chromosomal aberrations in bone marrow plasma cells of 102 patients with AL amyloidosis,analyzing the potential associations between clinical indicators,immunophenotype of plasma cells and iFISH results.Ｒｅｓｕｌｔｓ：There were 68 of 102 (6667%) patients with AL amyloidosis identified chromosomal abnormalities by iFISH detection,including 35 cases (5147%) of t(11;14),22 cases (3235%) of 1q21 amplification,20 cases (2941%) of D13S319 deletion,19 cases (2794%) with RB1 deletion and 4 cases (588%) with p53 deletion.And the difference in involved and uninvolved free light chain (dFLC) was significantly higher in patients with abnormal iFISH (P=0001).Patients with both RB1 deletion and D13S319 deletion had higher dFLC than patients with other two types of chromosomal changes (P=0022).Patients with abnormal iFISH were compared according to the expression of CD19,CD56,and CD117The proportion of chromosomal abnormalities was significantly higher in the CD19negative group than in the CD19positive group (7353% vs 5000%,P=0026)Ｃｏｎｃｌｕｓｉｏｎ：The detection rate of genetic abnormality of bone marrow plasma cells in patients with AL amyloidosis is 6667%,of which t(11;14) is the most common finding.Plasma cytogenetic abnormalities are associated with higher dFLCCD19negative PCs have a higher incidence of genetic abnormalities than CD19positive PCs.