Flow Cytometric DNA Ploidy Analysis in Haemato-Lymphoid Neoplasms: An Analysis of 132 Cases.

Background

FxCycleTM Violet (FCV) based flow cytometric (FCM) DNA ploidy analysis is a rapid and simple tool that can substantiate in characterizing the biological behaviour across the spectrum of haematological malignancies and correlates with cytogenetic studies. Materials and

Methods

In this prospective study, we performed simultaneous immunophenotyping with FCV based on ploidy analysis in n=132 consecutive new samples, comprising n=110 samples of haemato-lymphoid neoplasms, including acute leukemias (n=67, 60.9%), CML with myeloid blast crisis (n=1, 0.9%), MDS with excess blasts (n=2, 1.8%), mature B cell/ T cell neoplasms (n=37, 33.7%), multiple myeloma (n=3, 2.7%) along with n=22 normal samples. The FCM DNA data was compared with corresponding conventional karyotyping results, wherever available.

Results

In FCM ploidy analysis (n=110), the overall DNA index (DI) ranged from 0.81 to 2.17 and S-Phase fraction (SPF) from 0.1-31.6%. Diploidy was seen in n = 90 (81.8%), low-hyperdiploidy in n = 10 (9.1%), high-hyperdiploidy in n = 7 (6.4%) with one case each (0.9% each) having near-tetraploidy, high-hypodiploidy and low-hypodiploidy. The DI of all viable cell populations in normal samples ranged from 0.96-1.05. Conventional karyotyping was performed in n=76/110 cases (70%) with n= 11/76 (15%) culture failures. The modal chromosome number ranged from 45 to 63. A concordance of 95.4% (n=62/65) was noted with corresponding FCM DI.

Conclusion

FCV-based ploidy is a sensitive technique that provides complementary information and ascertains a strong correlation with conventional cytogenetics across all haemato-lymphoid neoplasms. It can detect aneuploidy in all B-ALL and myeloma cases, even in hemodiluted samples with cytogenetic culture failure; supplement the diagnoses of erythroleukemia, and provide a useful screen for a higher grade lymph node disease in lymphoma cases with SPF > 3%.