Indolent Lymphomas That Present With Clinically Aggressive Features: A Subset of Low-Grade Lymphomas With a Behavior Inconsistent With the Histologic Diagnosis

Immunohistochemical expression of transcription factors PAX5, OCT2, BCL6 and transcription regulator P53 in Non-Hodgkin lymphomas: A diagnostic cross-sectional study

Background

Non-Hodgkin lymphoma represents a heterogeneous group of tumors that constitute the seventh most common malignancy. Immunohistochemistry plays a major role in the detection of specific cell receptors. Transcription factors are a heterogeneous group of genes that play a critical role in the commitment, differentiation, and proliferation of specific cell types.

Methods

Paraffin-embedded tissue sections of non-Hodgkin lymphoma cases were selected, classified, and evaluated before staining with immunohistochemical markers (PAX5, OCT2, BCL6, and P53). Expression of the aforementioned markers was compared with histological subtypes and grades of lymphoma cases. Means of expression were also compared among histological subtypes.

Results

A total of 55 cases of NHL including 26 cases of low-grade lymphomas and 29 cases of high-grade lymphomas were included in the study. DLBCL and FL were the most common subtypes of high-grade and low-grade lymphomas respectively. Both PAX5 and OCT2 were positive in 44 cases of NHL (80%) including all cases of B-cell lymphomas. BCL6 and P53 demonstrated positive expression in 29.1% and 67.3% respectively. Interestingly, we found a significant association between the histological subtypes and the aforementioned markers (P-value<0.05).

Discussion

Expression of PAX5, OCT2, BCL, and P53 played a major role in the diagnosis and grading of non-Hodgkin lymphomas in our study. Both PAX5 and OCT2 provided more accuracy and specificity in the diagnosis of B-cell neoplasms compared to the classical B-cell markers. BCL6 expression reflected its role in germinal center formation in normal and malignant lymphoid tissues, and expression of P53 mirrored the accumulation of gene mutations in more aggressive lymphoma subtypes.

Conclusion

In this manuscript, we aimed to present a unique study that highlights the immunohistochemical expression of all the aforementioned factors among various histological subtypes of non-Hodgkin lymphomas with disparities in histological aggressiveness, highlighting a promising diagnostic and prognostic panel for non-Hodgkin lymphomas.

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Transcription factors are essential for the differentiation of B-cells.

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PAX5 and OCT2 provide more accuracy in the diagnosis of lymphomas.

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BCL6 expression reflects its role in germinal center formation.

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P53 expression is higher in aggressive subtypes.

Transformation of low-grade follicular lymphoma with partial marginal zone differentiation: Two cases

Two cases of low-grade follicular lymphoma, with marginal zone differentiation and/or with high proliferation rate in one of them, are reported with transformation into high grade B-cell and B-lymphoblastic lymphomas. The contribution of these features to the transforming process, although previously described, is infrequent, and has not been deciphered to date.

SHC014748M, a novel selective inhi-bitor of PI3Kδ, demonstrates promising preclinical antitumor activity in B cell lymphomas and chronic lymphocytic leukemia

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SHC014748M was proved to be more selective for PI3Kδ inhibition relative to other class i PI3K enzymes.

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SHC014748M showed in vitro activity in most of 23 B lymphoma cell lines and primary CLL cells and also inhibited phosphorylation of AKT, targets downstream of PI3Kδ.

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In vivo study revealed that SHC014748M significantly reduced lymphoma cell growth in the treatment group compared with control mice.

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SHC014748M seemed to be a novel promising compound in the treatment of B cell lymphomas and CLL.

PI3Kδ (phosphatidylinositol 3-kinase-δ), one of the class I PI3Ks, is found expressed primarily in leukocytes and plays an essential role in B-cell development and function. This provides a rationale for the development of small molecule inhibitors that selectively target p110δ for patients with indolent non-Hodgkin lymphomas. Here in this paper, we comprehensively evaluated the in vitro and in vivo antitumor activity of SHC014748M, an oral selective inhibitor of PI3Kδ under Phase I clinical evaluation. Biochemical and cell-based assays were used to measure compound potency and selectivity in lymphoma cell lines as well as primary chronic lymphocytic leukemia (CLL) cells. Scid mice were subcutaneously inoculated with the SU-DHL-6 cell line. SHC014748M was more selective for PI3Kδ inhibition relative to other class I PI3K enzymes and showed in vitro activity in most of 23 B lymphoma cell lines and primary CLL cells. SHC014748M also inhibited phosphorylation of AKT, targets downstream of PI3Kδ, in both lymphoma cells and primary CLL cells. In vivo study revealed that SHC014748M significantly reduced lymphoma cell growth in the treatment group compared with control mice. CCL4, CCL17, CCL22 and CXCL13 in patient serum decreased sharply after SHC014748M treatment. According to the results, SHC014748M appeared to be a novel promising compound in the treatment of B cell lymphomas and CLL.

Fluorodeoxyglucose-Positron Emission Tomography Predicts Bone Marrow Involvement in the Staging of Follicular Lymphoma

BACKGROUND

Standard bone marrow biopsy (BMB) and bone involvement with follicular lymphoma (FL) on positron emission tomography (PET)/computed tomography (CT) both predict early clinical failure in FL. The key clinical question is whether PET/CT findings can obviate the need for BMB. The goal of this study was to determine the value of PET/CT in determining bone involvement in FL, using posterior iliac crest BMB as the gold standard.

MATERIALS AND METHODS

A total of 548 patients with newly diagnosed grade 1-3A FL were included. The presence, pattern, and location of bone involvement, spleen involvement, and standardized uptake values (SUVs) in the L3 vertebral body were recorded for all patients and compared with the BMB report.

RESULTS

Excluding patients with focal bone lesions on PET/CT, the sensitivity and specificity of PET/CT in detecting bone or marrow involvement, compared with BMB, were 53% and 88%, respectively. The sensitivity and specificity of spleen involvement on PET/CT in predicting a positive BMB were 55% and 86%, respectively. An L3 SUVmax of less than 2.0 resulted in a negative predictive value (NPV) of 96% for marrow involvement on BMB; an L3 SUVmean below 1.4 resulted in an NPV of 100%.

CONCLUSION

In newly diagnosed FL, PET/CT-detected bone and splenic involvement is highly specific for a positive BMB, and very low SUV values (<2.0 SUVmax and < 1.4 SUVmean ) in the lumbar spine have a high NPV for a negative BMB. Routine BMB may be obviated in these patients. BMB remains necessary to definitively exclude bone marrow involvement in a large majority of patients with a negative PET.

IMPLICATIONS FOR PRACTICE

Predicting early clinical failure in follicular lymphoma (FL) is important but difficult. Bone marrow involvement by FL is associated with early clinical failure, and determining this involvement is a key component of the initial staging. This study highlights that in certain patients, positron emission tomography/computed tomography is sufficient in determining bone or marrow involvement, without the need for a confirmatory bone marrow biopsy (BMB). An algorithm is provided based on these findings to help clinicians determine which patients would benefit from BMB and when it can be avoided.

Prognostic Factors in Patients with Low-Grade Nonhodgkin Lymphoma

Low-grade Nonhodgkin lymphoma (LG-NHL) is characterized by indolent clinical course, which consist of marginal zone lymphoma (MZL), follicular lymphoma (FL), chronic lymphocytic leukemia/small lymphocytic lymphoma, lymphoplasmacytic lymphoma, waldenstrom macroglobulinemia (WM) as the most common subtypes. Factors affecting prognosis and treatment need in these patients have long been the subject of research. A retrospective study was conducted with patients diagnosed with LG-NHL in Hematology Departments of two centres between 2010 and 2018. At the time of diagnosis, demographic and disease characteristics, hematological and biochemical parameters were examined. Using these data, treatment requirements, response and survival rates were calculated. The effect of parameters on survival and need to treatment were analyzed. 93 LG-NHL patients were included in this study. 40 (43%) of these patients were MZL, 28 (30.1%) were FL and 25 (26.8%) were others. In comparison of patients required treatment with patients without treatment, there was significant difference among the number of comorbidity, platelet count, neutrophil count, disease subgroups and ferritin levels. Logistic regression analysis revealed that disease subgroup (other than MZL and FL) and ferritin levels were independent risk factors for need to treatment. Only ferritin level was found to be associated with overall survival. The current study demonstrated an association between serum ferritin levels and prognosis in patients with LG-NHL. Given that it is easily available and low-cost, the initial ferritin level can be used as a prognostic marker for patients with indolent lymphoma.

Detection of extranodal and spleen involvement by FDG-PET imaging predicts adverse survival in untreated follicular lymphoma

Predicting early clinical failure in patients with untreated follicular lymphoma (FL) is important but difficult. This study aimed to determine the incidence and patterns of extranodal (EN) and spleen disease using PET/CT, and assess their utility in predicting early clinical failure. PET/CT images from 613 cases of untreated FL (2003-2016) were reviewed. The location and number of EN sites, patterns of bone involvement, and splenic involvement were recorded. Outcomes were assessed using event-free survival (EFS), overall survival (OS), and early clinical failure at 24 months (EFS24). So, 49% (301/613) of patients had PET/CT-detected EN involvement, and 28% (171/613) had spleen involvement. The presence of ≥2 EN sites, spleen, bone or soft tissue involvement all predicted failure to achieve EFS24. Presence of ≥2 EN sites and bone involvement pattern were also predictive of OS in a univariate analysis. In a multivariate analysis with FLIPI-2 factors, spleen involvement, pattern of bone involvement, and soft tissue involvement independently predicted a lower EFS (HR 1.49 (1.11-2.00), P = .007; HR 1.71 (1.10-2.65), P = .017; and HR 1.67 (1.06-2.62), P = .026, respectively). When the multivariate analysis was performed using PRIMA-PI factors (marrow and B2M), the number of EN sites was an independent prognostic factor for inferior OS (HR 2.28; P = .05). Baseline PET/CT identifies EN involvement in nearly half of patients with untreated FL. The presence of ≥2 EN sites, bone, soft tissue, or splenic involvement predicts early clinical failure. These results, when combined with other factors, may better identify high-risk patients and guide therapy.