Association of quantitative assessment of the intrafollicular proliferation index with outcome in follicular lymphoma

Ki67 proliferation index in follicular lymphoma is associated with favorable outcome in patients treated with R-CHOP

Follicular lymphoma (FL) is a common, indolent small B-cell lymphoma. While the Follicular Lymphoma International Prognostic Index is widely used, reliable prognostic and predictive biomarkers are needed. A recent study suggested that architectural patterns of CD10, BCL6, and Ki67 expression may correlate with progression-free survival (PFS) in FL patients treated with chemotherapy-free regimens. We examined the prognostic and predictive utility of architectural patterns of CD10, BCL6, Ki67, and FOXP1 in 90 patients treated with immunochemotherapy (bendamustine-rituximab [BR] and R-cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP]). We found that high follicular Ki67 (≥30%) was associated with longer PFS in the subgroup of patients treated with R-CHOP but not among those treated with BR. Validation of this biomarker may support routine use of Ki67 as a predictive marker in FL.

Multicolor flow cytometric assessment of Ki67 expression and its diagnostic value in mature B-cell neoplasms

Background

There is no unified standard data about the sensitivity and specificity regarding flow cytometry analysis of Ki67 expression during lymphoma diagnoses.

Objective

This evaluated the efficacy of multicolor flow cytometry (MFC) in an estimate of the proliferative activity of B-cell non-Hodgkin lymphoma by comparing the expression of Ki67 using MFC and immunohistochemicals (IHC).

Method

A total of 559 patients with non-Hodgkin B-cell lymphoma were immunophenotyped using sensitive MFC, of which 517 were newly diagnosed and 42 were transformed lymphomas. Test samples include peripheral blood, bone marrow, various body fluids, and tissues. Through MFC multi-marker accurate gating, abnormal mature B lymphocytes with restricted expression of the light chain were screened. Ki67 was added to determine the proliferation index; the positive rate of Ki67 in tumor B cells was evaluated by cell grouping and internal control. For tissue specimens, MFC and IHC analyses were performed simultaneously to assess the Ki67 proliferation index.

Results

The positive rate of Ki67 by MFC was correlated with the subtype and aggressiveness of B-cell lymphoma. Ki67 could distinguish indolent lymphomas from aggressive subtypes with a cut-off value of 21.25%, and differentiate transformation from indolent lymphoma with a cut-off value of 7.65%. The expression of Ki67 by MFC (regardless of the type of samples)was highly agreement with the Ki67 proliferative index of tissue samples assessed by pathologic immunohistochemistry. MFC showed a fairly constant negative bias in evaluating tissue or bone marrow samples, compared with IHC.

Conclusions

Ki67 is a valuable flow marker that can distinguish between indolent and aggressive types of lymphoma and assess whether indolent lymphomas are transformed. Using MFC to evaluate the positive rate of Ki67 is important in clinical settings. MFC has unique advantages in judging the aggressiveness of lymphoma in samples of bone marrow, peripheral blood, pleural and ascites, and cerebrospinal fluid. This is particularly important when tissue samples cannot be obtained, making it an important supplement for pathologic examination.

Prognostic significance of histologic grade and Ki-67 proliferation index in follicular lymphoma

The prognostic value of histologic grading and the Ki-67 proliferation index in follicular lymphoma (FL) is controversial. This study investigated the clinical usefulness of these two factors in Asian FL patients. Four hundred and thirty-three patients diagnosed with FL were retrospectively reviewed with a median follow-up time of 47.0 months (range, 24.0-168.0). The 10-year overall survival (OS) rate and progression-free survival (PFS) rate were 91.0% and 47.1%, respectively. Grade 3B and grade 3B with diffuse large B cell lymphoma (DLBCL) showed a better PFS than grade 1-3A (P < 0.001), and similar findings were noted in patients who received rituximab-containing regimens (P = 0.002). In contrast, no significant differences in terms of OS or PFS were observed between grades 1-2 and 3A. In addition, patients with Ki-67 ≥ 30% had a significantly better PFS than patients with Ki-67 < 30% (P = 0.014), although the difference was eliminated in the multivariate analysis. Both grade and Ki-67 index had no impact on prognosis in patients who did not receive rituximab treatment. In conclusion, grade 3A is closely related to grade 1-2, as reflected by a similar indolent clinical course and a lower PFS rate than grade 3B/3B + DLBCL. In addition, a higher Ki-67 index seems to have a positive effect on PFS in FL patients.

Time from diagnosis to 2nd treatment is a promising surrogate for overall survival in patients with advanced stage follicular lymphoma

It is difficult to demonstrate an overall survival (OS) benefit in trials of immediate therapy vs observation in follicular lymphoma (FL). Time to 2nd treatment (TT2T) may be a preferred endpoint. We identified 584 consecutive patients at our institution with advanced stage FL grade 1-3 A for whom intention was observation (n = 248) or therapy (n = 338). Median time to 1st treatment (TT1T), TT2T, and OS were estimated (subdistribution function). Modified Kendall's tau (mKτ) was used to assess correlation between survival endpoints. Among initially observed patients, median TT1T was 3.3 years, TT2T was 12.1 years, 10-year treatment-free survival was 23%, and 10-year OS was 82%. TT2T was strongly correlated with OS following initial observation (mKτ 0.46, p = .004) or therapy (mKτ 0.53, p < .0001), while duration of observation was not. TT2T is a potential surrogate for OS. Given the outstanding survival in this population, early intervention trials should focus on identifying high risk patients.

Extrafollicular PD1 and Intrafollicular CD3 Expression Are Associated With Survival in Follicular Lymphoma

INTRODUCTION

Both microenvironment and tumor biomarkers impact outcome in follicular lymphoma (FL). We aimed to study the effect of Ki-67, CD3, CD68, and PD1 expression on outcome of FL.

MATERIALS AND METHODS

Forty-eight patients were included. Stained slides were visually assessed and marker expression was correlated with outcome. Both intra- and extrafollicular expression of Ki-67, CD68, and PD1 were evaluated. CD3 was evaluated only in the intrafollicular area. The median values of expression served as a cutoff point for low- and high-expression groups.

RESULTS

High extrafollicular PD1 expression predicted superior FFTF (freedom from treatment failure) compared with low expression (5-year 52% vs. 44%, P = .04). Five-year FFTF markedly increased from 37% to 67% (P = .057) in patients with low intrafollicular CD3 expression.

CONCLUSION

Our study supports the hypothesis that survival in FL depends on the immunologic cross talk between malignant cells and microenvironment; however, the specific types of cells that influence the clinical behavior of FL are still unknown.