Genetic variation and risk of chronic lymphocytic leukaemia

The Role of HOX Transcription Factors in Cancer Predisposition and Progression

Homeobox (HOX) transcription factors, encoded by a subset of homeodomain superfamily genes, play pivotal roles in many aspects of cellular physiology, embryonic development, and tissue homeostasis. Findings over the past decade have revealed that mutations in HOX genes can lead to increased cancer predisposition, and HOX genes might mediate the effect of many other cancer susceptibility factors by recognizing or executing altered genetic information. Remarkably, several lines of evidence highlight the interplays between HOX transcription factors and cancer risk loci discovered by genome-wide association studies, thereby gaining molecular and biological insight into cancer etiology. In addition, deregulated HOX gene expression impacts various aspects of cancer progression, including tumor angiogenesis, cell autophagy, proliferation, apoptosis, tumor cell migration, and metabolism. In this review, we will discuss the fundamental roles of HOX genes in cancer susceptibility and progression, highlighting multiple molecular mechanisms of HOX involved gene misregulation, as well as their potential implications in clinical practice.

Clinical presentation and hematological profile among young and old chronic lymphocytic leukemia patients in Sudan

OBJECTIVE

To assess the clinical presentation and hematological profile among young (≤ 55 years) and old (> 55 years) chronic lymphocytic leukemia patients in Sudan.

RESULT

In the present cross-sectional descriptive study, out of 110 cases studied, among them 31 (28.2%) were young (≤ 55 years) patients with mean age 48 years, and 79 (71.8%) were elder patients (> 55 years) with mean age 66 years, the overall mean age was 62.97 ± 12.06 with range (22-85 years), and 79 (71.8%) were males and 31 (28.2%) were females (M:F = 2.6:1) (P = 0.000). (7.3%) were asymptomatic, 61 (55.5%) presented with nonspecific complains. Generalized lymphadenopathy was seen in 52 (47.27%) with elder predominance (P = 0.03). Splenomegaly, hepatomegaly, thrombocytopenia and anemia were seen in 54 (49.1%), 14 (12.7%), 43 (39.1%) and 38 (34.5%) of patients respectively with male predominance. 54 (49.1%) and 42 (38.18%) of patients presented at Rai high risk and Binet C stages respectively with nearly same age and sex distribution. CLL in Sudan is a disease of elders, same as seen in literature, with high male to female ratio. In general hematological parameters means were noted to be distributed equally according to age and sex groups. Majority of patients were presented with nonspecific symptoms and nearly half of patients presented at late stages as reported in most developing countries.

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia among the adults in the Western World. CLL (and the corresponding nodal entity small lymphocytic lymphoma, SLL) is classified as a lymphoproliferative disorder characterised by the relentless accumulation of mature B-lymphocytes showing a peculiar immunophenotype in the peripheral blood, bone marrow, lymph nodes and spleen. CLL clinical course is very heterogeneous: the majority of patients follow an indolent clinical course with no or delayed treatment need and with a prolonged survival, while others experience aggressive disease requiring early treatment followed by frequent relapses. In the last decade, the improved understanding of CLL pathogenesis shed light on premalignant conditions (i.e., monoclonal B-cell lymphocytosis, MBL), defined new prognostic and predictive markers, improving patient stratification, but also broadened the therapeutic armamentarium with novel agents, targeting fundamental signaling pathways.

Associations of non-Hodgkin Lymphoma (NHL) risk with autoimmune conditions according to putative NHL loci

Autoimmune conditions and immune system-related genetic variations are associated with risk of non-Hodgkin lymphoma (NHL). In a pooled analysis of 8,692 NHL cases and 9,260 controls from 14 studies (1988-2007) within the International Lymphoma Epidemiology Consortium, we evaluated the interaction between immune system genetic variants and autoimmune conditions in NHL risk. We evaluated the immunity-related single nucleotide polymorphisms rs1800629 (tumor necrosis factor gene (TNF) G308A), rs1800890 (interleukin-10 gene (IL10) T3575A), rs6457327 (human leukocyte antigen gene (HLA) class I), rs10484561 (HLA class II), and rs2647012 (HLA class II)) and categorized autoimmune conditions as primarily mediated by B-cell or T-cell responses. We constructed unconditional logistic regression models to measure associations between autoimmune conditions and NHL with stratification by genotype. Autoimmune conditions mediated by B-cell responses were associated with increased NHL risk, specifically diffuse large B-cell lymphoma (odds ratio (OR) = 3.11, 95% confidence interval (CI): 2.25, 4.30) and marginal zone lymphoma (OR = 5.80, 95% CI: 3.82, 8.80); those mediated by T-cell responses were associated with peripheral T-cell lymphoma (OR = 2.14, 95% CI: 1.35, 3.38). In the presence of the rs1800629 AG/AA genotype, B-cell-mediated autoimmune conditions increased NHL risk (OR = 3.27, 95% CI: 2.07, 5.16; P-interaction = 0.03) in comparison with the GG genotype (OR = 1.82, 95% CI: 1.31, 2.53). This interaction was consistent across major B-cell NHL subtypes, including marginal zone lymphoma (P-interaction = 0.02) and follicular lymphoma (P-interaction = 0.04).

SAMHD1: a new gene for CLL

In this issue of Blood, Clifford et al broaden the horizons of chronic lymphocytic leukemia (CLL) genetics by adding SAMHD1 to the compendium of driver genes recurrently mutated in this tumor.1,2

Candidate gene association studies and risk of chronic lymphocytic leukemia: a systematic review and meta-analysis

To evaluate the contribution of association studies of candidate polymorphisms to inherited predisposition to chronic lymphocytic leukemia (CLL), we conducted a systematic review and meta-analysis of published case-control studies. We identified 36 studies which reported on polymorphic variation in 19 genes and CLL risk. Out of the 23 polymorphic variants, significant associations (p < 0.05) were seen in pooled analyses for only four variants: MDR1, rs1045642; LTA, rs2239704; CD38, rs6449182; and IFNGR1, rs4896243. These findings should be interpreted cautiously, as the estimated false positive report probabilities (FPRPs) for each association were not noteworthy (i.e. FPRP > 0.2). While studies of candidate polymorphisms may be an attractive means of identifying risk factors for CLL, the limited power of published studies to demonstrate statistically significant associations makes it essential that future analyses be based on sample sizes well-powered to identify variants having modest effects on CLL risk.

Analysis of activation-induced cytidine deaminase mRNA levels in patients with chronic lymphocytic leukemia with different cytogenetic status

Activation induced cytidine deaminase (AID) enzyme, which converts cytosine into uracil and is expressed only by activated B lymphocytes, plays a role in B cells in both the mechanisms of somatic hypermutation (SHM) and class switch recombination (CSR). There are studies showing that AID can cause numerous translocations in different lymphoproliferative diseases. Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of monoclonal B cells in bone marrow and peripheral blood. The predictability and clinical status of B-CLL are difficult to determine. About 30-50% of patients have chromosomal abnormalities. AID, which is thought to create fraction segments for translocations, might also cause deletions in DNA regions of 17p13, 11q22.3, 13q14 and 13q34 that are associated with prognostic implications in patients with CLL. In this study, the AID gene expression in patients with CLL with and without deletions was investigated. When compared to healthy subjects and patients without deletions, increased levels of AID expression in patients with deletions of 17p13, 11q22.3 or 13q14 were found, but not for the 13q34 region. Our results show that AID expression may be associated with deletions in patients with CLL.

Familial occurrence of chronic lymphocytic leukaemia in Norway

BACKGROUND

The only known risk factor for chronic lymphocytic leukaemia (CLL) is occurrence of the disease in close relatives. The aim of this study was to determine the frequency of familial chronic lymphocytic leukaemia.

MATERIAL AND METHOD

All patients with chronic lymphocytic leukaemia notified to the Cancer Registry in the period 1.10.2007-31.12.2009 were asked to report occurrences of malignant disease in siblings, parents, grandparents and children. The information about malignant haematological disease was verified with the Cancer Registry.

RESULTS

We found malignant haematological disease in close relatives of 42 of the 236 included patients (18%). CLL and lymphoma were the most common diagnoses. On average, 16 family members were identified in each family. The relative risk of developing CLL was six times higher in those who had close relatives with the disease (16 of a total of 3,776 family members) than among those who did not have close relatives who were affected (76 cases among 107,223 family members of 38,159 control subjects). The increased risk of disease was also associated with other lymphoproliferative diseases. With patrilinear, but not matrilinear inheritance, we found a birth order effect, with affection of younger men in a group of siblings, while the eldest escaped.

INTERPRETATION

Malignant haematological disease is common in the family members of patients with CLL. CLL is the most common disease, but there is extensive pleiotropy.

Analysis of clinical characteristics of 516 patients with non-Hodgkin's lymphoma in Shanghai area

The aim was to determine the clinical and cytogenetic characteristics of non-Hodgkin's lymphoma (NHL) in Shanghai. A retrospective analysis was conducted in 516 patients with NHL. Patient clinical data, including age, sex, diagnosis, immunophenotypes, and karyotypes, were collected. The median age was 58 years. There was a male predominance in all NHL, except extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. Patients with B cell NHL (1.5%) expressed CD3. T cell NHL patients (11.5%) expressed CD20. Epstein-Barr virus latent integral membrane protein 1, BCL6, CD10, Bcl-2, CD68, myeloperoxidase, CD99, CD30, CD15, and CD43 were present in various types of NHL. Complex karyotypes accounted for 92.3% of the 73.7% patients with abnormal karyotypes. Immunoglobin heavy chain gene translocation was present in 60.3% of B cell and 23.7% of T/NK cell neoplasms. Understanding the complex clinicopathological and molecular features of NHL may help with prognosis and serve as targets for treatments.

Incidence and mortality trends of leukemia and lymphoma in Croatia, 1988-2009

AIM

To investigate the time trends of leukemia and lymphoma in Croatia from 1988-2009, compare them with trends in other populations, and identify possible changes.

METHODS

The data sources were the Croatian National Cancer Registry for incidence data, Croatian Bureau of Statistics for the numbers of deaths, and United Nations population estimates. Joinpoint regression analysis using the age-standardized rates was used to analyze incidence and mortality trends.

RESULTS

Acute lymphoblastic leukemia and chronic lymphocytic leukemia incidence did not significantly change. Acute myeloid leukemia incidence significantly increased in women, with estimated annual percentage change (EAPC) of 2.6% during the whole period, and in men since 1998, with EAPC of 3.2%. Chronic myeloid leukemia incidence significantly decreased in women (EAPC -3.7%) and remained stable in men. Mortality rates were stable for both lymphoid and myeloid leukemia in both sexes. Hodgkin lymphoma non-significantly increased in incidence and significantly decreased in mortality (EAPCs of -5.6% in men and -3.7% in women). Non-Hodgkin lymphoma significantly increased in incidence in women (EAPC 3.2%) and non-significantly in men and in mortality in both men (EAPC 1.6%) and women (EAPC 1.8%).

CONCLUSION

While Croatia had similar leukemia and lymphoma incidence trends as the other countries, the mortality trends were less favorable than in Western Europe. The lack of declines of leukemia incidence and non-Hodgkin lymphoma mortality could be attributed to late introduction of optimal therapies. As currently the most up-to-date diagnostics and treatments are available and covered by health insurance, we expect more favorable trends in the future.