CCND1-IGH Fusion-Amplification and MYC Copy Number Gain in a Case of Pleomorphic Variant Mantle Cell Lymphoma

Modeling tissue-specific breakpoint proximity of structural variations from whole-genomes to identify cancer drivers

Structural variations (SVs) in cancer cells often impact large genomic regions with functional consequences. However, identification of SVs under positive selection is a challenging task because little is known about the genomic features related to the background breakpoint distribution in different cancers. We report a method that uses a generalized additive model to investigate the breakpoint proximity curves from 2,382 whole-genomes of 32 cancer types. We find that a multivariate model, which includes linear and nonlinear partial contributions of various tissue-specific features and their interaction terms, can explain up to 57% of the observed deviance of breakpoint proximity. In particular, three-dimensional genomic features such as topologically associating domains (TADs), TAD-boundaries and their interaction with other features show significant contributions. The model is validated by identification of known cancer genes and revealed putative drivers in cancers different than those with previous evidence of positive selection.

Cytological Diagnosis of Aggressive Small-Cell Lymphomas

BACKGROUND

Despite their sometimes deceivingly bland appearance, some small-cell lymphomas are very aggressive and the prognosis of patients depends on a prompt diagnosis that allows the initiation of appropriate therapy.

SUMMARY

The present review discusses the salient cytological features of the most common aggressive small-cell lymphomas and then proceeds to analyze their main diagnostic criteria, including the usage of ancillary techniques.

KEY MESSAGES

Lymph node fine-needle aspiration cytology is a fast, safe, cheap, minimally invasive, and accurate procedure that can be used for a prompt and accurate diagnosis of lymphomas.

Mantle cell lymphoma presenting with lethal atraumatic splenic rupture

Mantle cell lymphoma is characterized by t(11;14) with CCND1-IGH fusion and manifests with a spectrum of disease ranging from relatively indolent to aggressive. Here, we present a case of pleomorphic mantle cell lymphoma with three fusion signals that presented with lethal atraumatic splenic rupture. We discuss on the implications of variant CCND1 signal patterns as well as the epidemiology and pathophysiology of atraumatic splenic rupture.

MYC rearrangement but not extra MYC copies is an independent prognostic factor in patients with mantle cell lymphoma

Mantle cell lymphoma (MCL) with MYC rearrangement (MYC-R) is rare and little is known about the importance of MYC extra copies (EC) in the absence of MYC-R in MCL patients. This study includes 88 MCL patients with MYC tested by fluorescence in situ hybridization and/or conventional cytogenetics, including 27 with MYC-R, 21 with MYC-EC, and 40 with normal (NL) MYC. MCL patients with MYC-R more often had blastoid/pleomorphic morphology; a higher frequency of CD10, MYC, and simultaneous MYC and BCL2 expression; a higher level of MYC; and a higher Ki67 proliferation rate (p<0.05) than those without MYC-R. Although patients with MYC-R more frequently received aggressive chemotherapy (p=0.001), their overall survival (OS) was significantly shorter than those without MYC-R. Compared with patients with MYC/BCL2 double hit lymphoma (DHL), patients with MYC-R MCL had a similar OS but more commonly had bone marrow involvement, stage 4 disease, and a different immunophenotype. MCL patients with MYC-EC showed an OS intermediate between those with MYC-R and MYC-NL, either all or only blastoid/pleomorphic MCL patients included. Multivariate analysis showed that MYC-R, but not MYC-EC, had an independent and negative impact on OS. In conclusion, MYC-R but not MYC-EC showed a higher MYC expression and is an adverse prognostic factor for MCL patients. Although the OS of MCL patients with MYC-R is similar to that of MYC/BCL2 DHL patients, these groups have different clinicopathologic features supporting the retention of MCL with MYC-R in the category of MCL, as recommended in the revised World Health Organization classification.

An Uncommon Case of Double-Hit Mantle Cell Lymphoma That Demonstrates a Transformation Process

OBJECTIVES

Mantle cell lymphoma (MCL) is a mature B-cell lymphoma characterized by CCND1/IGH rearrangement. We reported a case of MCL harboring both CCND1/IGH and MYC/IGH rearrangements that also presented with an aggressive clinical course.

METHODS

Biopsy specimens were evaluated by morphological staining, immunohistochemistry, flow cytometry, conventional cytogenetics, fluorescence in situ hybridization (FISH), and next-generation sequencing (NGS).

RESULTS

Morphological and immunohistochemical staining of gallbladder samples demonstrated blastoid variant MCL. However, in the bone marrow sample, FISH indicated rearrangements in CCND1/IGH and MYC/IGH. Flow cytometry identified two groups of malignant lymphocytes. We sorted these two groups of cells. NGS then revealed that both cell types carried CCND1/IGH rearrangements and TP53 mutations. Furthermore, the CD19+/CD10+ cells carried additional MYC/IGH rearrangement and NOTCH2 mutation.

CONCLUSIONS

The rearrangement of MYC and a mutation in NOTCH2 probably induced the transformation of MCL cells in this patient. This uncommon double-hit MCL case clearly demonstrates a transformation process.

Prognostic significance of aberrant CD5 expression in B-cell leukemia

Aberrant expression of CD5 (as a T-cell marker) is seen in some leukemia and lymphoma of B lineage origin. Given that the signaling resulting from the expression of this marker plays an essential role in the development of leukemia and lymphoma, evaluating the expression of this marker is of paramount importance. Therefore, our goal in this study was to investigate the prognostic importance of CD5 expression in B-cell leukemia and lymphoma. We evaluate CD5 expression in normal and leukemic B-cells by identifying relevant literature through a PubMed search (1998-2018) of English language papers using the terms: ‘CD5,’ ‘B-cell,’ ‘Leukemia,’ and ‘Lymphoma.’ We are doing this thorough comparison of results from CD5 positive and negative cases to make a correct decision about prognostic importance of CD5 expression in these malignancies. In a number of B-cell malignancies, CD5 is expressed in varying degrees. Due to the different origins and characteristics of these malignancies, the results of CD5 expression evaluations are heterogeneous and impossible to generalize. However, CD5 expression is sometimes associated with clinicopathologic findings, more invasive clinical course, and even resistance to treatment (specifically in DLBCL) among CD5- positive patients, which appears to be a function of CD5 signaling and its downstream factors such as STAT3. Depending on the type of malignancy, CD5 expression is associated with good or bad prognosis, which can be used as an auxiliary prognostic factor to assess the clinical course of B-cell malignancies. Moreover, the difference in expression levels of CD5 in a variety of B-cell malignancies allows for differential diagnosis of these malignancies, which can be helpful when diagnosis is difficult.