Heterogeneity of neoplastic and reactive cell proliferation in non-Hodgkin's lymphomas linked to patient survival

Tumor-infiltrating T cells in primary cutaneous B-cell lympho-proliferative disorders

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are considered to play an important role in the antitumoral immune response. The presence and percentage of CD8-positive tumor-infiltrating T cells have been shown to correlate with differentiation and prognosis in various neoplasms. The aim of this study was to determine the number of CD8-positive T cells in various primary cutaneous B-cell lymphoproliferative disorders and to evaluate its correlation with the histological type of tumor.

METHODS

Fifty-three lesions were examined by immunohistochemistry with antibodies targeting CD3, CD4, CD8 and TIA-1. Thirty-two lesions had been diagnosed as primary cutaneous B-cell lymphomas (CBCL) and 21 as B-cell pseudolymphomas (B-PSL). CBCLs included 15 follicular lymphomas (FL), 6 marginal zone lymphomas (MZL), and 11 diffuse large B-cell lymphomas (LCL). The number of CD8-positive cytotoxic T cells was determined by computer-assisted morphometrical microscopy.

RESULTS

No significant difference could be detected in the density of CD8-positive T cells in B-PSL (101/105 microm(2)), FL (110/105 microm(2)), and MZL (122/105 microm(2)). In contrast, the number of CD8-positive cells (55/105 microm(2)) in LCL was significantly lower (p<0.01) compared to B-PSL, FL and MZL.

CONCLUSIONS

In summary the number of CD8-positive T cells in B-cell lymphoproliferative disorders differs in regard to tumor type and differentiation with lowest numbers in diffuse large B-cell lymphomas. However, due to an overlap of the number of TILs, this parameter cannot be employed as a diagnostic parameter for individual cases.

CDK1 and cyclin A expression is linked to cell proliferation and associated with prognosis in non-Hodgkin's lymphomas

Cellular proliferation is regulated by several kinasic complexes associating cyclins and their catalytic subunits cyclin-dependent kinases (CDKs). In order to gain insight into the mechanisms underlying proliferation in non-Hodgkin's lymphoma (NHL), we examined the expression of certain cell cycle regulatory proteins normally expressed in lymphoid cells, cyclins A, B, D3 and E and cdk1, 2, 4, and 6. In 70 patients presenting a previously untreated lymphoma, cyclins and CDKs were studied by Western blotting and quantified by densitometry. Flow cytometry study of DNA content was carried out for all patients in order to study cell proliferation and level of ploidy. The results were analysed according to the histological types, the immunological phenotypes of the lymphomas and the outcome of the patients. Cdkl and cyclin A were correlated with the percentage of cells in S and S+G2/M phases, and significantly different according to the grade of malignancy, with the lowest expression in low-, and the highest in high-grade NHL according to the Working Formulation. In B-NHLs, cdk1, cyclin A, as well as cdk2, cyclin D3 and E expression was higher in the aneuploid than in the euploid group. Our results point to some particularities of cell cycle regulation in two lymphoma sub-types: 1) a low expression of cyclin D3 and cdk6 in mantle cell lymphomas and 2) a discrepancy between the high proliferative activity and the level of protein expression in Burkitt's lymphomas. CDK1 and cyclin A showed a significant prognostic value for achievement of complete remission (Cdk 1) and for both disease free (cyclin A) and overall survival (cyclin A and cdk1): low protein level was associated with the best prognosis in B-NHLs. Our results show that differential cell cycle regulating protein expression may be associated with different biological and clinical behaviour of NHLs and confirm the usefulness of the study of cell cycle regulation as a tool for understanding lymphoid malignancies.

S-phase fraction by the labeling index as a predictive factor for progression and survival in low grade non-Hodgkin's lymphoma

BACKGROUND

The purpose of this study was to learn if the bromodeoxyuridine labeling index (LI), a measure of the S-phase fraction, is an independent prognostic factor for overall survival (OS) for patients with newly diagnosed low grade non-Hodgkin's lymphoma (NHL). In addition, the ability of the LI to predict time to progression (TTP) in a group of patients observed without therapy after initial diagnosis was determined.

METHODS

Patients eligible for this study had biopsy proven low grade NHL, adequate tissue to perform the LI, and were previously untreated. The bromodeoxyuridine LI was performed on fresh biopsy samples using a slide-based immunofluorescence procedure.

RESULTS

One-hundred twelve patients were followed prospectively for OS, and 50 of these patients who initially were observed without therapy were eligible for an analysis of TTP. The LI (< or = 1% vs. > 1%) and presence of "B" symptoms were significant univariate prognostic factors for survival (P values of 0.004 and < 0.001, respectively). In a multivariate analysis, the LI and symptoms retained independent prognostic significance, whereas disease stage, histologic subtype, and age did not. In the group who were observed after diagnosis, the LI was not an independent predictor of TTP.

CONCLUSIONS

The LI at initial diagnosis is an independent prognostic factor for OS of patients with low grade NHL, but it does not help choose patients for observation without therapy. Measurements of the LI should be considered as part of the on-study evaluation of patients entering cooperative group trials evaluating new therapies for this group of lymphomas.