CD138 Enrichment Strategy and Results of Chromosome Genomic Array Testing (CGAT) for Multiple Myelomas

      Background: CD138 enrichment of multiple myeloma (MM) samples significantly improves the FISH detection rate. In a pilot study of 46 patients, we previously showed CD138 enrichment with abnormal plasma cells by flow between 0.5% ~ 40% dramatically improved detection rate by CGAT: 85% abnormal by CGAT and 89% abnormal by FISH with 80% concordance. CGAT found additional markers in 83% of the samples, 6.5% of which were not detected by FISH. In 15% of the cases, FISH uniquely detected low-level abnormalities. Methods: Based on these findings, the MM Pathway testing scheme was implemented. CD138+enrichment was performed on samples with 0.01% ~ 0.5% plasma cells for FISH only, on samples with >0.5% ~ 6% plasma cells for both FISH and CGAT, and >6% ~ 40% for CGAT only. Since implementation, 306 total MM samples were tested. We compared results from 130 of the samples with concurrent karyotype, FISH and CGAT. Results: Overall detection rate was 99.2%, with abnormal karyotype in 40%, abnormal CGAT in 93%, and abnormal FISH in 98.5%. Concordance between FISH and CGAT for high-risk imbalances was consistently >90%. Besides common MM abnormalities, CGAT found frequent losses of X, 6q, 14q, and 16q and cnLOH of chromosomes 1, 4, 12, 14, and 16q. A strong association of 14q cnLOH with t(11;14) was observed, and chromosome 4 abnormalities often concur with 16q aberrations, half of which were cnLOH. Conclusions: CD138 enrichment is important for MM testing. Our Pathway testing scheme with judicious use of CGAT and FISH based on plasma cell content offers maximum diagnostic yield.
      To read this article in full you will need to make a payment


      Subscribe to Cancer Genetics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect