Prognostic implications of histologic grade and intensity of Bcl-2 expression in follicular lymphomas undergoing rituximab-containing therapy

Follicular lymphoma grade 3A: aggressiveness and curability in an Asian cohort of 781 patients

Follicular lymphoma grade 3A (FL3A) is an uncommon subtype of FL with histology falling between FL grade 1/2 (FL1/2) and FL grade 3B (FL3B). The behavior of FL3A is currently debated, with some studies suggesting it may be potentially curable while others deem it incurable. However, the lack of large-scale studies with prolonged follow-up and changes in prognosis due to the use of rituximab (R) call for further investigation into the clinical course, prognosis, and treatment of FL3A in the R era. We conducted a follow-up for a median of 7.3 years (30% exceeded 10 years) on 104 FL3A cases who received R-CHOP/R-CHOP-like treatment. We compared the characteristics, clinical behavior, and prognosis of the FL3A group with control groups of DLBCL (n = 478), FL3B (n = 45), and FL1/2 (n = 154). Based on R-CHOP/like therapy, FL3A had similar outcomes to FL3B and DLBCL, with comparable 5-year and 10-year PFS and OS rates. Follow-up revealed that both FL3A and FL3B showed PFS platform 6 years after treatment initiation, while DLBCL had low recurrence rates (< 2%) after 5 years. FL1/2 showed persistent recurrence. No significant difference was observed in PFS among the four groups (p = 0.955) (Fig. 2A). Based on R-CHOP/R-CHOP-like regimen treatment, the OS of FL3A, FL3B and DLBCL manifested no statistically significant differences (p = 0.812), although FL3A appears to exhibit the poorest long-term survival in the curve, but FL1/2 showed better OS than the other three groups (p <0.001) (Fig. 2B). The period most at risk for recurrence was within the first year after initial treatment. Follicular Lymphoma International Prognostic Index (FLIPI) predicted PFS and OS for low-risk patients in FL3A, while FLIPI-2 was more effective in describing prognosis for high-risk patients in terms of PFS and OS. Based on treatment with R-CHOP/like, the prognosis of FL3A is comparable to that of FL3B and DLBCL. FL3A exhibits a PFS platform at 6 years post-initial treatment. FL3A had potential disease aggressiveness and curability.

High frequency of BCL2 gene rearrangement-negative follicular lymphoma in northwestern Italy

BCL2 rearrangement is reported to be an early pathogenetic event in follicular lymphoma (FL) and it is considered as a reliable marker in the follow up of the disease. We aimed to investigate the frequency of BCL2 rearrangement in FLs from northwestern Italy, to evaluate their clinicopathological features, and to investigate alternative genetic aberrations in BCL2-negative FLs. We collected a series of 76 consecutive FLs diagnosed between 2013 and 2016. All lymphomas underwent histopathological review. Interphasic fluorescent in situ hybridization (FISH) was performed with break apart probes targeting BCL2, IGH, BCL6 and MYC on paraffin embedded (PE) and fresh frozen (FF) specimens. 1p36 region and p53 locus in BLC2-negative cases were investigated using dual color probes. Karyotype analysis was available in a subset of cases. BCL2 rearrangements were detected in 39 cases (51,3%). Of the remaining 37, 6 showed IGH rearrangement, and were further tested: 1 showed variant BCL2 translocation, 1 had BCL6 rearrangement, and the other 4 were negative for further gene rearrangements. FISH on FF specimens detected small BCL2+ clones in cases otherwise categorized as BCL2-. 1p36 and p53 deletion were observed in 1 and 8 BCL2- FLs, respectively. Karyotype analysis documented 3q, 1p and BCL6 alternative abnormalities in 3 cases. In conclusion, BCL2 rearrangement is not a constant finding in FL, its frequency being probably affected by geographical factors. Thus, it should not be considered as a reliable molecular marker in the follow up of the disease, unless it is found to be present at the initial diagnosis of FL. Alternative genetic aberrations exist in BCL2-negative cases.

Differences in clinical characteristics and outcomes between patients with grade 3a and grades 1-2 follicular lymphoma: a real-world multicenter study

BACKGROUND

The difference between clinical characteristics and outcomes between follicular lymphoma grade 1-2 (FL1-2) and FL3a defined pathologically remains unclear, resulting in uncertainty how to treat FL3a. However, it may be crucial for clinicians to discriminate grade 3a and grade 1-2 for predicting prognosis and thus making treatment decisions.

METHODS

We compared 1403 patients with FL1-2 and 765 patients with FL3a diagnosed between January 2000 and December 2020 from fifteen centers nationwide in China to describe differences in clinical characteristics and outcomes.

RESULTS

Compared with FL1-2 patients, FL3a subgroup had a higher percentage of elderly patients (P = 0.003), and relatively more FL3a patients presented with increased levels of LDH (P < 0.0001) and higher Ki-67 indexs greater than 30% (P < 0.001). More FL3a patients were treated with CHOP ± R (P < 0.0001), and fewer were treated with the watchful-waiting approach (P < 0.0001). The results showed a higher incidence of relapse among FL3a patients, in which more patients underwent histological transformation (HT) when compared to FL1-2 (P = 0.003). 1470 (76.2%) patients of the entire cohort received R-CHOP therapy; survival analysis revealed that FL3a patients had a worse progression-free survival (PFS) rate than FL1-2 patients. Survival of FL3a patients with respect to FLIPI showed an inferior PFS in the intermediate and high-risk groups than FL1-2 patients. FL3a patients had a much worse prognosis than FL1-2 with or without progression of disease within 24 months (POD24). FL3a patients had higher likelihood of lymphoma-related death (LRD, P < 0.05), whereas the rates for non-LRD were comparable.

CONCLUSION

In conclusion, this study demonstrates a marked difference in clinical features and outcomes in FL3a patients compared with FL1-2 patients. The results highlight the need for applying therapeutic approaches distinct from FL1-2 when treating FL3a patients.

Diagnostic clues of BCL2-negative, faint, or controversial follicular lymphomas: a study of 103 cases

BCL2 positivity by immunohistochemistry is helpful for the diagnosis of follicular lymphoma (FL); however, a minority of FL cases are BCL2-negative, and the diagnosis is thus challenging. We retrospectively analyzed the incidence, morphology, immunophenotype, and genetic status of BCL2¹⁺ (weakly/focally positive by clone 124), BCL2⁰ (negative), and BCL2^{controversial} FLs compared with BCL2²⁺ (strongly positive) FLs to clarify diagnostic clues. In 1068 FL cases, 103 (10%) with BCL2¹⁺ (37 cases, 4%), BCL2⁰ (61 cases, 6%), or BCL2^{controversial} (5 cases, 0.5%) were included in the final analysis. BCL2¹⁺ and BCL2⁰ FLs tended to have limited stage disease, nodal disease, and grades 3A/3B histology and showed a higher complete response rate than BCL2²⁺ FLs. Among 103 BCL2⁰, BCL2¹⁺, or BCL2^{controversial} FL cases, 34 (33%) had a diffuse area composed of CD20-positive small-to medium-sized lymphoid cells, a feature of low-grade B-cell lymphoma. Interfollicular dense CD20-positive cells and interfollicular clusters of CD10-positive cells were observed in 59% and 37% of cases, respectively. In remaining 13/40 cases (33%), BCL2 was converted to BCL2²⁺ by other clones E17/SP66. CD23 and MUM1 were positive in 10/40 (25%) and 1/40 (3%) cases, respectively. IGH/BCL2 fusion and clonality were detected in 6/37 (16%) and 31/34 (91%) cases, respectively. In conclusion, morphological examination of the distribution of CD20-and/or CD10-positive cells and the presence of diffuse area could be used to diagnose FL in most cases. The majority of the remaining FL cases could be diagnosed using other BCL2 clones and clonality analyses.

A Favorable Outcome of Grade 3 Follicular Lymphoma Treated With Surgery and Obinutuzumab Combined With Chemotherapy: A Case Report and Literature Review

Follicular lymphoma is the most common type of low-grade non-Hodgkin lymphoma and the second most common type of lymphoma. Primary extranodal follicular lymphoma is rare compared with nodular follicular lymphoma involving the gastrointestinal (GI) tract. There has been uncertainty regarding follicular lymphomas due to the heterogeneous presentation and severity in which they present. However, studies showed that patients diagnosed with primary gastrointestinal follicular lymphoma do not typically differ in their presentation from those diagnosed with nodular follicular lymphoma involving the GI tract. Furthermore, recent literature identifies that patients diagnosed with grade 3 follicular lymphoma tend to have similar genetic and molecular entities to those diagnosed with diffuse large B-cell lymphoma (DLBCL). Based on these results, current studies have shown that patients with grade 3 follicular lymphoma who are treated with anthracycline-based regimens have similar outcomes to those with diffuse large B-cell lymphoma. However, additional studies are warranted to demonstrate the benefit of managing grade 3 follicular lymphoma with more aggressive anthracycline/rituximab-based regimens. Here, we present a case of a 44-year-old male diagnosed with grade 3 follicular lymphoma involving the gastrointestinal tract, who demonstrated an excellent treatment response following therapy similar to the treatment of bulky diffuse large B-cell lymphoma despite a tumor burden size below 7.5 cm.

High-grade Follicular Lymphomas Exhibit Clinicopathologic, Cytogenetic, and Molecular Diversity Extending Beyond Grades 3A and 3B

Although follicular lymphoma (FL) is usually graded as FL1-2, FL3A, and FL3B, some borderline cases can be observed and led us to investigate the clinicopathologic diversity of grade 3 FL (FL3). Among 2449 FL patients enrolled in Lymphoma Study Association (LYSA) trials, 1921 cases with sufficient material underwent a central pathologic review. The resulting diagnoses comprised 89.6% FL1-2 (n=1723), 7.2% FL3A (n=138), and 0.5% purely follicular FL3B (n=9). The remaining 51 unclassifiable cases (2.7%) exhibited high-grade features but did not meet WHO criteria for either FL3A or FL3B; and were considered as "unconventional" high-grade FL (FL3U). FL3U morphological pattern consisted of nodular proliferation of large cleaved cells or small-sized to medium-sized blast cells. Compared with FL3A, FL3U exhibited higher MUM1 and Ki67 expression, less BCL2 breaks and more BCL6 rearrangements, together with a higher number of cases without any BCL2, BCL6 or MYC rearrangement. FL3U harbored less frequent mutations in BCL2, KMT2D, KMT2B, and CREBBP than FL3A. MYC and BCL2 were less frequently mutated in FL3U than FL3B. Rituximab cyclophosphamide, doxorubicin, vincristine, and prednisone treated FL3U patients had a worse survival than FL1-2 patients with similar follicular lymphoma international prognostic index and treatment. These results suggest that high-grade FLs encompass a heterogeneous spectrum of tumors with variable morphology and genomic alterations, including FL3U cases that do not strictly fit WHO criteria for either FL3A or FL3B, and display a worse outcome than FL1-2. The distinction of FL3U may be useful to allow a better comprehension of high-grade FLs and to design clinical trials.

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.

Evaluating Novel PET-CT Functional Parameters TLG and TMTV in Differentiating Low-grade Versus Grade 3A Follicular Lymphoma

BACKGROUND

Follicular lymphoma (FL) grading, low-grade 1-2 (LG) versus grade 3A (3A), informs management. However, accurate grading is challenging owing to disease heterogeneity and inter-reader variability. The [18F]-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) parameter maximum standardized uptake value (SUVmax) has utility in differentiating LG from 3A FL, but the utility of novel parameters total lesion glycolysis (TLG) and total metabolic tumor volume (TMTV) is unknown.

PATIENTS AND METHODS

Retrospective review of diagnostic pre-treatment PET-CTs of patients aged > 18 years with FL grades 1-3A from 2009-2017 was performed. PET-CT parameters SUVmax, TLG, and TMTV values were generated using manual (MW) and semi-automated workflows (SW). Poisson regression and receiver operating characteristic curves were used to compare PET-CT parameters between LG and 3A.

RESULTS

A total of 49 patients with FL were identified: 38 LG and 11 3A. PET-CT parameters were significantly higher in 3A as compared with LG in both workflows. The cutoff values, sensitivities, and specificities were as follows: SUVmax: 10.4, 64%, and 74% in MW and 11.9, 73%, and 76% in SW; TLG: 543, 82%, and 74% in MW and 371, 73%, and 74% in SW; and TMTV: 141, 73%, and 76% in MW and 93, 64%, and 76% in SW. SUVmax had identical cutoff, sensitivity, and specificity across all 3 SWs, whereas TLG and TMTV had considerable variance across all 3 SWs.

CONCLUSIONS

TLG and TMTV are comparable to SUVmax in differentiating LG versus 3A FL. Cutoffs, sensitivities, and specificities varied in MW versus SW. Novel PET-CT parameters serve as reproducible adjuncts but not replacements for biopsy in differentiating grades of FL.

Long-term outcome comparing histological grades of follicular lymphoma patients treated with immunochemotherapy as first-line therapy: A retrospective analysis from two institutions

OBJECTIVES

To clarify the impact of histological grades in follicular lymphoma.

METHODS

We retrospectively analysed 250 patients diagnosed with FL treated with chemoimmunotherapy: 188 patients were grades 1-2 and 62 grade 3A.

RESULTS

In our series, grade 3A FL patients were older, higher proportion of localised disease and lower bone marrow infiltration at diagnosis comparing grades 1-2 FL patients. Estimated six-year progression-free survival and time to progression showed no differences between both groups [grade 3A: 56% (95%CI: 39%-73%) and 51% (95%CI: 41%-61%) vs grades 1-2:55% (95%CI: 46%-63%) and 57% (95%CI: 49%-65%), P = .782 and P = .521, respectively]. Estimated six-year overall survival was lower, 76% (95%CI: 64%-88%) for the grade 3A group than grades 1-2 83% (95%CI: 77%-89%); P = .044. In addition to that, cumulative incidence curves of death not related to lymphoma at 10 years between groups were as follows: [0.26 (95%CI: 0.25-0.27) and 0.05 (95%CI: 0.04-0.06) for G3AFL and G1-2FL, respectively], P = .010. Grade 3A FL showed in PFS curve no relapses after 6 years. These results were absolutely reproduced in 199 patients receiving R-CHOP regimen as induction.

CONCLUSIONS

Our results indicate similar long-term outcomes in terms of progression-free survival and time to progression in grades 1-2 and 3A. No relapses were observed in G3AFL group after 6 years.

Limited stage grade 3 follicular lymphoma patients can experience favorable outcomes with combined modality therapy

Controversy exists regarding the optimal management of limited stage grade 3 follicular lymphoma (FL3). We assessed the treatment outcomes of 190 consecutive patients with stage I-II FL. Fifty two patients had FL3 disease, in whom the median age was 55 years. At a median follow-up of 65 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 76.6% and 87.6%, respectively. Patients receiving systemic therapy followed by radiation therapy (RT) had a significantly better PFS (p=.003) than those treated with RT alone, but similar OS (p = .476). Patients treated with RT had 100% local control. Compared to 132 patients with grade 1-2 FL, those with FL3 had similar PFS (p = .493) and OS (p  =  .330). Patients with FL3 can experience favorable outcomes when treated with a combination of systemic therapy and RT, comparable to low grade FL.

Definitive radiotherapy for localized follicular lymphoma staged by 18F-FDG PET-CT: a collaborative study by ILROG

Radiotherapy (RT) can be curative in patients with localized follicular lymphoma (FL), with historical series showing a 10-year disease-free survival of 40 to 50%. As ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography with computerized tomography (PET-CT) upstages 10 to 60% of patients compared to CT, we sought to evaluate outcomes in patients staged by PET-CT, to determine if more accurate staging leads to better patient selection and results. We conducted a multicenter retrospective study under the direction of the International Lymphoma Radiation Oncology Group (ILROG). Inclusion criteria were: RT alone for untreated stage I to II FL (grade 1-3A) with dose equivalent ≥24 Gy, staged by PET-CT, age ≥18 years, and follow-up ≥3 months. End points were freedom from progression (FFP), local control, and overall survival (OS). A total of 512 patients treated between 2000 and 2017 at 16 centers were eligible for analysis; median age was 58 years (range, 20-90); 410 patients (80.1%) had stage I disease; median RT dose was 30 Gy (24-52); and median follow-up was 52 months (3.2-174.6). Five-year FFP and OS were 68.9% and 95.7%. For stage I, FFP was 74.1% vs 49.1% for stage II (P < .0001). Eight patients relapsed in-field (1.6%). Four had marginal recurrences (0.8%) resulting in local control rate of 97.6%. On multivariable analysis, stage II (hazard ratio [HR], 2.11; 95% confidence interval [CI], 1.44-3.10) and BCL2 expression (HR, 1.62; 95% CI, 1.07-2.47) were significantly associated with less favorable FFP. Outcome after RT in PET-CT staged patients appears to be better than in earlier series, particularly in stage I disease, suggesting that the curative potential of RT for truly localized FL has been underestimated.

Chemotherapy-Free Initial Treatment of Advanced Indolent Lymphoma Has Durable Effect With Low Toxicity: Results From Two Nordic Lymphoma Group Trials With More Than 10 Years of Follow-Up

PURPOSE

For indolent lymphoma, the optimal timing, sequence, and choice of therapeutic regimens remain a matter of debate. In two Nordic Lymphoma Group randomized trials, symptomatic or clearly progressing patients were treated first line with a rituximab-containing regimen without chemotherapy. The purpose of this study was to assess long-term survival, risk of transformation, and need of new therapies.

METHODS

Data were collected at cross-sectional follow-up for 321 patients with indolent lymphoma (84% with follicular lymphomas [FL]) included in one of two Nordic Lymphoma Group trials (accrual 1998 to 1999 and 2002 to 2008). All patients received first-line therapy with one or two cycles of four weekly infusions of rituximab 375 mg/m2, and 148 were randomly allocated to the addition of interferon alfa-2a. Follow-up data were retrieved from initial trial databases and medical records on repeated clinical evaluations.

RESULTS

At the end of follow-up, 73% of patients were alive, with a median follow-up after random assignment of 10.6 years. Among all, 36% (38% with FL) had never needed chemotherapy. For patients with FL who required new therapy within 24 months because of early disease progression, the 10-year survival rate was 59% versus 81% for those with longer remission. Interferon was not shown to improve long-term outcome. Transformation was diagnosed in 20% of all patients (2.4% per person-year) and in 18% with FL. An additional malignancy was found in 12%.

CONCLUSION

Approximately one third of patients with symptomatic indolent lymphoma (30% with FL, 23% without FL) did not need new therapy in the long term after first-line rituximab without chemotherapy. In the entire cohort, 10-year survival was excellent with no major safety issues, which suggests that chemotherapy can be delayed safely in the majority of patients.

Follicular Lymphoma Diagnostic Caveats and Updates

CONTEXT.—

Follicular lymphoma is a common small B-cell lymphoma, likely to be encountered by any practicing pathologist, regardless of specialty. Although the features of typical follicular lymphoma are well known and in most instances easily identifiable, there are lesser-appreciated morphologic appearances that can raise alternative diagnostic possibilities. The limited tissue available in core needle biopsies can make it additionally challenging to thoroughly evaluate those features in the context of architecture. Furthermore, ancillary testing including immunohistochemistry and molecular/genetic analysis do not always show classic findings and may pose additional challenges to interpretation.

OBJECTIVES.—

To review the morphologic features of follicular lymphoma with a discussion of morphologic variants and mimics; to discuss pitfalls of ancillary testing and provide the practicing pathologist with an appropriate context for interpretation of immunohistochemical and molecular/genetic studies when follicular lymphoma is part of the differential diagnosis; and to propose diagnostic strategies when there is limited tissue for evaluation.

DATA SOURCES.—

We used examples of follicular lymphoma from our institution as well as a review of the literature, with a focus on the diagnostic aspects that are broadly relevant to a general pathology practice.

CONCLUSIONS.—

Follicular lymphoma can occasionally present with atypical morphologic, immunohistochemical, or molecular/genetic features. In particular, those findings can be difficult to interpret in the setting of a limited tissue sample. Awareness of those possibilities will help guide the pathologist to a more accurate and precise diagnosis.

[Clinical characteristics and survival analysis of de novo grade 3 or transformed follicular lymphoma patients]

Objective: To evaluate the clinical characteristics and survival outcomes of patients with de novo grade 3 or transformed follicular lymphoma (FL). Methods: Fifty-two patients treated at Peking University Cancer Hospital between January 2009 and September 2017 were assessed, including 28 patients with FL 3A grade, 13 patients with FL 3B grade, 11 patients with transformed FL. Baseline characteristics, survival and prognostic factors were analyzed. Results: ① Twenty-six male and 26 female patients were enrolled, including 28 patients with FL 3A grade, 13 patients with FL 3B grade, 11 patients with transformed FL. ②The 3-year progression-free survival (PFS) and overall survival (OS) for the entire cohort were 56.0% and 80.6%, respectively. Patients with international prognostic index (IPI) score 0-1 demonstrated significantly better 3-year PFS (80.3% vs 20.1%; t=18.902, P<0.001) and OS (95.7% vs 57.0%; t=10.406, P<0.001) than patients with IPI score 2-3. Three-year PFS (94.1% vs 37.2% vs 25.2%; P=0.002) and OS (100.0% vs 76.0% vs 59.8%; P=0.020) were also significantly different among patients with FLIPI 1 score 0-1, 2, ≥3. FLIPI 2 score was also identified as a prognostic factor for 3-year PFS (68.4%, 0, 0; P=0.001) and OS(87.5%, 76.2%, 0; P=0.003). ③Multivariate analysis indicated a significant association of PFS (HR=3.536, P=0.015) and OS (HR=15.713, P=0.015) with IPI. FLIPI 2 was associated with OS (score 0-1, HR=0.078, P=0.007; score 2, HR=0.080, P=0.022). Conclusion: De novo grade 3 or transformed FL might be a group of curable disease with current treatment strategies. IPI is still a prognostic tool in this scenario.

Apoptosis regulator Bcl-2 is an independent prognostic marker for worse overall survival in triple-negative breast cancer patients

BACKGROUND

The objective of this study was to examine the prognostic significance of carbonic anhydrase IX (CAIX), an endogenous marker for tumor hypoxia; the cellular tumor antigen p53; and the apoptosis regulator Bcl-2, in triple-negative breast cancer (TNBC) patients.

METHODS

Immunohistochemically determined expression of CAIX, p53, Bcl-2 and proliferation factor Ki-67, analyzed in 64 paraffin-embedded TNBC tissue samples, was used to assess their relation to clinicopathological variables and prognostic implications for overall survival (OS).

RESULTS

Bcl-2 expression was negatively correlated with histological grade of tumor, while expression of p53 was positively correlated with the same clinical variable (p = 0.036 and p = 0.033, respectively). The p53 expression was also positively correlated with tumor size (p = 0.010). Survival analysis showed that patients with high Bcl-2 expression (above cutoff value determined by receiver operator characteristic [ROC] curve analysis) had shorter OS (p = 0.020). The same was observed for patients with tumors larger than 5 cm (p = 0.034) or positive lymph nodes (p = 0.004). Among all 3 examined markers, multivariate analysis showed that only Bcl-2 expression was a strong independent prognostic indicator for decreased OS (hazard ratio [HR] = 15.16, 95% confidence interval [95% CI], 2.881-79.727, p = 0.001).

CONCLUSIONS

Elevated expression of Bcl-2 was an independent prognostic factor for poorer OS in TNBC and as such a significant marker for tumor aggressiveness.

Clinical impact of molecular features in diffuse large B-cell lymphoma and follicular lymphoma

Our understanding of the pathogenesis and heterogeneity of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) has been dramatically enhanced by recent attempts to profile molecular features of these lymphomas. In this article, we discuss ways in which testing for molecular features may impact DLBCL and FL management if clinical trials are designed to incorporate such tests. Specifically, we discuss how distinguishing lymphomas on the basis of cell-of-origin subtypes or the presence of other molecular features is prognostically and therapeutically significant. Conversely, we discuss how the molecular similarities of DLBCL and FL have provided insight into the potential of both DLBCL and FL cases to respond to agents targeting alterations they have in common. Through these examples, we demonstrate how the translation of our understanding of cancer biology into improvements in patient outcomes depends on analyzing the molecular correlates of treatment outcomes in clinical trials and in routinely treated patients.

Inter- and intratumoral heterogeneity of BCL2 correlates with IgH expression and prognosis in follicular lymphoma

Most follicular lymphomas (FLs) are genetically defined by the t(14;18)(q32;q21) translocation that juxtaposes the BCL2 gene to the immunoglobulin heavy chain (IgH) 3' regulatory regions (IgH-3'RRs). Despite this recurrent translocation, FL cases are heterogeneous in terms of intratumoral clonal diversity for acquired mutations and variations in the tumor microenvironment. Here we describe an additional mechanism that contributes to inter- and intratumoral heterogeneity in FLs. By applying a novel single-molecule RNA fluorescence-based in situ hybridization (FISH) technique to detect mRNA molecules of BCL2 and IgH in single cells, we found marked heterogeneity in the number of BCL2 mRNA transcripts within individual lymphoma cells. Moreover, BCL2 mRNA molecules correlated with IgH mRNA molecules in individual cells both in t(14;18) lymphoma cell lines and in patient samples. Consistently, a strong correlation between BCL2 and IgH protein levels was found in a series of 205 primary FL cases by flow cytometry and immunohistochemistry. Inter- and intratumoral heterogeneity of BCL2 expression determined resistance to drugs commonly used in FL treatment and affected overall survival of FL patients. These data demonstrate that BCL2 and IgH expressions are heterogeneous and coregulated in t(14;18)-translocated cells, and determine the response to therapy in FL patients.