Flow cytometric S‐phase fraction as a complementary biological parameter for the cytological grading of non‐Hodgkin's lymphoma

Abstract

Fine-needle aspiration cytology (FNAC) is a technique that can overcome tissue-sampling disaggregation problems related to DNA flow cytometry analysis. The aim of this study, with long-term follow-up (median, 72 mo), was to investigate the prognostic value of DNA ploidy and S-phase fraction (SPF) in patients with non-Hodgkin's lymphoma (NHL), and additionally, the relevance of SPF in the grading of NHLs, using FNAC. The series comprised 76 patients with NHL (32 indolent and 44 aggressive tumors, including 14 Burkitt lymphomas) and 30 patients with reactive lymph node enlargement used as a control group. DNA flow cytometry was performed on fresh samples obtained by FNAC. NHL grading was done according to the updated Kiel classification. The 5-yr overall survival of patients with NHL was determined using the Kaplan-Meier method. All samples of the control group and 81.6% of the NHLs showed a DNA diploid pattern. Fourteen cases (18.4%) were DNA aneuploid with bimodal distribution: slight hyperdiploidy and near-tetraploidy. Despite the higher incidence of aneuploidy in aggressive than in indolent tumors (22.7% vs. 12.5%), no correlation between DNA ploidy and NHL grading was observed. In contrast, SPF revealed a strong correlation with grading (P=0.0001). The mean SPF values varied from 6.5% in indolent NHLs, to 20.4% in aggressive not-otherwise-specified (NOS) NHLs, and to 35.3% in Burkitt lymphomas. Nearly all aggressive NHLs had an SPF >15%, while the vast majority of indolent NHLs showed an SPF <10%. The mean SPF value in the reactive node group was 6.6%. NHL grading significantly was correlated to survival (P=0.004) only if the Burkitt lymphomas, which showed the best prognosis, were analyzed as an independent group. There was a trend that did not reach statistical significance (P=0.072) for a worse clinical outcome of patients with aneuploid tumors. When mean SPF values were used as cutoff points to divide both indolent NHLs and aggressive NOS NHLs into two proliferative subgroups, no differences in relation to survival were found (P=0.763 and P=0.994, respectively). Also, no proliferative difference was verified between indolent NHLs and the reactive lymph node group (P=0.223). These results show that flow cytometric SPF is a valuable complementary parameter for grading NHLs on FNAC samples, but it appears to give no additional prognostic information on subset analyses.

Association between the proliferative rate of neoplastic B cells, their maturation stage, and underlying cytogenetic abnormalities in B-cell chronic lymphoproliferative disorders: analysis of a series of 432 patients

“…3,69,70 Previous reports indicate that B-CLPDs displaying a low proliferative rate correspond to relatively indolent, low-grade tumors, while B-CLPDs with a higher proliferative rate typically (Ͼ 10%) show an aggressive clinical course. 23,25,28 In line with these observations, we found a clear association between higher percentages of S ϩ G2/M cells and both adverse prognostic features (eg, advanced patient performance status, disease stage, high LDH serum levels, and presence of thrombocytopenia), progressive disease, and a shorter overall survival for the whole B-CLPD group as well as for a specific diagnostic subgroups of the disease such as MCL.…”

“…Interestingly, upon comparing the DNA index (DI) of aneuploid cases, significant differences were observed between B-CLL cases (DI of 1.05 Ϯ 0.04) in comparison with MCL (DI of 1.6 Ϯ 0.4; P Ͻ .001), FL (DI of 1.3 Ϯ 0.4; P Ͻ .001), DLBCL (DI of 1.4 Ϯ 0.4; P Ͻ .001), and BL (DI of 1.4 Ϯ 0.2; P ϭ .01) patients, in line with previous observations. 21,24,28,29,54 In addition, FL cases also showed a significantly lower DNA index than MCL cases (P ϭ .02). Among B-CLL patients, DNA aneuploidy was associated with a higher percentage of S ϩ G2/M-phase cells (1% Ϯ 0.7% vs 0.5% Ϯ 0.7%; P ϭ .002) as previously reported.…”

“…Such comparison could contribute to a better understanding of the real impact of specific genetic abnormalities in the proliferation rate of tumor cells arrested at specific stages of maturation; in turn, this information is also of potential clinical relevance, since measurement of the proliferative activity of neoplastic cells by semiquantitative immunohistochemical techniques (eg, ki67 or PCNA immunostaining), 14-19 3 H thymidine incorporation, 20 and single-parameter flow cytometric analysis of paraffin-embedded tumor samples [21][22][23][24][25][26][27] is considered to be of great help for the prognostic stratification of B-cell chronic lymphoproliferative disorders (B-CLPDs), [21][22][23][26][27][28][29][30][31][32][33] even within specific histologic and WHO subtypes (eg, mantle cell lymphoma). 34 Despite this, evaluation of tumor cell proliferation has only partially translated into routine clinical practice.…”

The Usefulness of CD71 Expression by Flow Cytometry for Differentiating Indolent From Aggressive CD10+ B-Cell Lymphomas

“…Neither FSC nor CD71i significantly differentiated follicular lymphoma (FL) grades. A comparison of all FLs (grades [1][2][3] and non-FL high-grade lymphomas (Burkitt lymphoma [BL] and large B-cell lymphoma [LBCL]) showed significant differences in CD71i (P < .001) and FSC (P = .021). Differences were significant in CD71i and FSC between FL and LBCL (P < .001) but not between FL and BL.…”

Distribution of Ki67 Proliferative Indices among WHO Subtypes of Non-Hodgkin's Lymphoma: Association with other Clinical Parameters

“…Estimation of proliferative index as a marker of tumor aggressiveness has long been known. Several methods to assess proliferative fraction of tumor cells have been identified, of which flow cytometric determination of S-phase fraction gained most popularity (Pinto et al, 2003). Ki67 is a nuclear antigen that is expressed in mid G1, S, G2 and M phase of the cell cycle (Gerdes et al, 1984).…”