SDF1/CXCL12 (-801GA) polymorphism is a prognostic factor after treatment initiation in Waldenstrom macroglobulinemia

New Insights on the Emerging Genomic Landscape of CXCR4 in Cancer: A Lesson from WHIM

Deciphering the molecular alterations leading to disease initiation and progression is currently crucial to identify the most relevant targets for precision therapy in cancer patients. Cancers express a complex chemokine network influencing leucocyte infiltration and angiogenesis. Moreover, malignant cells also express a selective repertoire of chemokine receptors that sustain their growth and spread. At present, different cancer types have been shown to overexpress C-X-C chemokine receptor type 4 (CXCR4) and to respond to its ligand C-X-C motif chemokine 12 (CXCL12). The CXCL12/CXCR4 axis influences cancer biology, promoting survival, proliferation, and angiogenesis, and plays a pivotal role in directing migration of cancer cells to sites of metastases, making it a prognostic marker and a therapeutic target. More recently, mutations in the C-terminus of CXCR4 have been identified in the genomic landscape of patients affected by Waldenstrom's macroglobulinemia, a rare B cell neoplasm. These mutations closely resemble those occurring in Warts, Hypogammaglobulinemia, Immunodeficiency, and Myelokathexis (WHIM) syndrome, an immunodeficiency associated with CXCR4 aberrant expression and activity and with chemotherapy resistance in clinical trials. In this review, we summarize the current knowledge on the relevance of CXCR4 mutations in cancer biology, focusing on its importance as predictors of clinical presentation and response to therapy.

Working Toward a Genomic Prognostic Classification of Waldenström Macroglobulinemia: C-X-C Chemokine Receptor Type 4 Mutation and Beyond

Waldenström macroglobulinemia is a rare indolent B-cell lymphoma. Whole-exome sequencing studies have improved our knowledge of the Waldenström macroglobulinemia mutational landscape. The MYD88 L265P mutation is present in nearly 90% of patients with Waldenström macroglobulinemia. CXCR4 mutations are identified in approximately 30% of MYD88L265P cases and have been associated with ibrutinib resistance in clinical trials. Mutations in CD79B, ARID1a, or TP53 were described at lower frequency. Deciphering the earliest initiating lesions and identifying the molecular alterations leading to disease progression currently represent important goals in the future to identify the most relevant targets for precision therapy in Waldenström macroglobulinemia.

Somatic mutations in MYD88 and CXCR4 are determinants of clinical presentation and overall survival in Waldenström macroglobulinemia

Activating MYD88 as well as nonsense and frameshift WHIM-like CXCR4 somatic mutations are common in WM. CXCR4 NS mutations are present in aggressive cases including hyperviscosity syndrome, and MYD88 status is a determinant of survival.

The genomic landscape of Waldenström macroglobulinemia is characterized by highly recurring MYD88 and WHIM-like CXCR4 mutations, and small somatic deletions associated with B-cell lymphomagenesis

Highly recurring mutations are present in WM, including MYD88 L265P, warts, hypogammaglobulinemia, infection, and myelokathexis-syndrome–like mutations in CXCR4, and ARID1A. Small, previously undetected CNAs affecting B-cell regulatory genes are highly prevalent in WM.

The bone marrow microenvironment in waldenstrom macroglobulinemia

Waldenstrom macroglobulinemia (WM) is a low-grade B-cell lymphoproliferative disorder characterized primarily by specific homing and growth of tumor cells within the bone marrow niches. The progressive growth of tumor cells throughout the bone marrow indicates that the tumor cells are capable of homing and adhering to specific niches that allow growth, survival and drug resistance. In this review we highlight the interaction of the tumor cells in WM and the bone marrow microenvironment including bone marrow stromal cells, endothelial cells and mast cells. Migration, adhesion and downstream activation of signaling pathways leads to cell trafficking and cell dissemination in WM. Future therapeutic agents need to target not only the tumor clone, but also its close interaction with the bone marrow microenvironment.

The bone marrow microenvironment in Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma characterized by widespread involvement of the bone marrow (BM). The BM microenvironment serves as not only a site for disease involvement, but it also appears that the interaction of WM cells with the BM is essential for the pathogenesis of WM. The BM microenvironment consists of the cellular and noncellular compartments. The BM has been shown to regulate cell proliferation, cell cycle, and drug resistance as well as cell dissemination and cell trafficking of WM cells. A better understanding of the role of the BM microenvironment in the pathogenesis of WM can help guide better therapeutic strategies that can target the tumor clone and also regulate the BM microenvironment.

Risk stratification in Waldenström macroglobulinemia

Waldenström macroglobulinemia is characterized by the production of serum monoclonal IgM and lymphoplasmacytic bone marrow infiltration. At least 25% of patients are asymptomatic at diagnosis and treatment is only mandatory in cases of symptomatic disease. Beside reports on treatment results, reviewing risk assessment is another way to describe the clinical course of the disease. This information may be particularly useful when numerous treatment options are available. While the introduction of new treatment approaches reinforces the need for careful risk assessment, the identification of useful prognostic information requires prolonged follow-up in patients who have not been treated with current therapeutic options. This limitation should be taken into account when using and interpreting available prognostic information, especially survival estimates.

Targeting the bone marrow in Waldenstrom macroglobulinemia

Waldenstrom macroglobulinemia (WM) is a low-grade B-cell lymphoma characterized by widespread involvement of the bone marrow with lymphoplasmacytic cells. In approximately 20% of patients, the malignant clone also involves the lymph nodes and induces hepatosplenomegaly. The mechanisms by which the tumor cells home to the bone marrow and preferentially reside in the marrow niches are not fully elucidated. In this review, we examine the role of the bone marrow microenvironment in the regulation of cell growth, survival and cell dissemination in WM. We also summarize specific regulators of niche-dependent tumor proliferation in WM. These include chemokines, adhesion molecules, Src/PI3K/Akt/mTOR signaling, NF-kB activation, and micro-RNA regulation in WM. Targeting these pathways in clinical trials could lead to significant responses in this rare disease.

New insights into the pathogenesis and treatment of Waldenstrom macroglobulinemia

PURPOSE OF REVIEW

Waldenstrom macroglobulinemia is a distinct low-grade lymphoproliferative disease. There have been recent significant advances in understanding the underlying pathogenesis of this disease, including genetic and epigenetic regulators of tumor progression.

RECENT FINDINGS

Current studies have shown that the tumor microenvironment plays a critical role in cell proliferation, dissemination, and drug resistance.

SUMMARY

This review provides an update of the advances in the pathogenesis of factors both intrinsic (in the tumor clone) and extrinsic (in the bone marrow microenvironment) that regulate tumor progression in Waldenstrom macroglobulinemia. We next discuss novel agents that have been recently tested in clinical trials based on the advances observed in the pathogenesis of Waldenstrom macroglobulinemia.

The bone marrow niche in Waldenström's macroglobulinemia

The widespread involvement of the bone marrow with tumor cells indicates that there is continuous cell trafficking of WM cells in and out of the bone marrow leading to cell dissemination in the bone marrow and in the lymph nodes in many patients with WM. The interaction of the WM cells with the bone marrow is critical for the regulation of cell proliferation, cell cycle, drug resistance as well as cell dissemination and trafficking. Advances in understanding the interaction of the tumor clone with the BM microenvironment have led to the development of therapeutic agents that not only target the tumor clone but also regulate the bone marrow microenvironment. Here, we review the role of the cellular and liquid bone marrow compartments in the regulation of cell proliferation and dissemination in WM.

Association of genetic polymorphisms of CXCL12/SDF1 gene and its receptor, CXCR4, to the susceptibility and prognosis of non-small cell lung cancer

BACKGROUND

The aim of this study was to evaluate the relations of chemokine CXCL12, previously known as stromal cell-derived factor-1 (SDF1), and its receptor, CXCR4, gene variants on non-small cell lung cancer (NSCLC) risk and disease severity.

METHODS

Through a case-control study design, genomic DNA samples of 247 NSCLC patients and 328 age and sex-matched controls were subjected to polymerase chain reaction-restriction fragment length polymorphism analysis. The validity of this technique was proven by direct sequencing of amplified products. Statistical analyses were conducted to explore the contribution of polymorphism of the CXCL12/SDF1 gene and CXCR4, in the susceptibility to and prognosis of NSCLC.

RESULTS

Overall, the genotype frequencies of CXCL12/SDF1 gene and CXCR4, were significantly different between lung cancer patients and controls (p<0.0001), and also different between patients with lung cancers of various stages (p<0.0001). Logistic regression analysis revealed that higher odds ratios (ORs) for lung cancer were seen for individuals with CXCL12/SDF1 AA (an OR of 1.95, 95% CI 1.08-3.50, p=0.018), or CXCR4 TT (an OR of 4.71, 95% CI 1.99-11.2, p<0.0001), and for individuals with both CXCL12/SDF1 AA and CXCR4 TT genotypes (an OR of 12.4, 95% CI 1.56-98.3, p=0.002). The patients carrying a homologous AA genotype at CXCL12/SDF1, or a homologous TT genotype at CXCR4, had a tendency to advanced disease and toward poorer prognoses compared with other patients.

CONCLUSION

A significant association between the polymorphisms of CXCL12/SDF1 and CXCR4, and the susceptibility to and prognosis of NSCLC was demonstrated.