Genomic characterization of high-count MBL cases indicates that early detection of driver mutations and subclonal expansion are predictors of adverse clinical outcome

High-count monoclonal B-cell lymphocytosis (MBL) is an asymptomatic expansion of clonal B-cells in the peripheral blood without other manifestations of chronic lymphocytic leukemia (CLL). Yearly, 1% of MBLs evolve to CLL requiring therapy; thus being critical to understand the biologic events that determine which MBLs progress to intermediate/advanced CLL. In this study, we performed targeted deep-sequencing on 48 high-count MBLs, 47 of them with 2-4 sequential samples analyzed, exploring the mutation status of 21 driver genes and evaluating clonal evolution. We found somatic non-synonymous mutations in 25 MBLs(52%) at the initial time-point analyzed, including 13(27%) with >1 mutated gene. In cases that subsequently progressed to CLL, mutations were detected 41 months (median) prior to progression. Excepting NOTCH1, TP53 and XPO1, which showed a lower incidence in MBL, genes were mutated with a similar prevalence to CLL, indicating the early origin of most driver mutations in the MBL/CLL continuum. MBLs with mutations at the initial time-point analyzed were associated with shorter time-to-treatment (TTT). Furthermore, MBLs showing subclonal expansion of driver mutations on sequential evaluation had shorter progression time to CLL and shorter TTT. These findings support that clonal evolution have prognostic implications already at the pre-malignant MBL stage, anticipating which individuals will progress earlier to CLL.

Pancreatic Cancer: Associations of Inflammatory Potential of Diet, Cigarette Smoking, and Long-Standing Diabetes

Background: Pancreatic cancer (PanC) is a rapidly lethal malignancy with poorly understood etiology. Epidemiologic studies show strong associations between PanC and inflammatory conditions or stimuli such as cigarette smoking and diabetes, suggesting that inflammation may play a key role in PanC. Studies of dietary patterns and cancer outcomes also suggest that diet might influence an individual's risk of PanC through modulation of inflammation. We, therefore, examined independent and joint associations between inflammatory potential of diet, cigarette smoking and long-standing type II diabetes (greater than 5 years) in relation to risk of PanC. Methods: Data were from a clinic-based, case-control study of rapidly ascertained patients with incident adenocarcinoma of the exocrine pancreas (n = 819) evaluated at Mayo Clinic and non-cancer control patients (n = 1,769) recruited from Mayo Clinic primary care facilities. Controls were frequency-matched to cases on age, race, and sex. Inflammatory potential of diet was measured using the dietary inflammatory index (DII), calculated from dietary intake assessed via a 144-item food frequency questionnaire and adjusted for energy intake. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for age, sex, race, body mass index, diabetes, smoking, and education. Results: Higher DII scores, reflecting a more pro-inflammatory diet, were associated with increased odds of PanC (OR Quintile5vs1 = 2.80, 95% CI, 2.06–3.79, Ptrend < 0.0001). Increased odds of PanC also were observed among current (OR = 2.55, 95% CI, 1.75–3.72) and former (OR = 1.26, 95% CI, 1.05–1.51) smokers as compared to non- smokers, and among participants with long-standing type II diabetes (OR = 2.96, 95% CI, 1.95–4.51) compared to non-diabetics. Joint associations were observed for the combined effect of having greater than the control median DII score and a) being a current smoker (OR = 4.20, 95% CI, 2.67–6.61),or b) having long-standing type II diabetes (OR = 6.13, 95% CI, 3.47–10.80) as compared to having less than or equal to the control median DII score and being a non-smoker or non-diabetic, respectively. Conclusion: These findings suggest that a pro-inflammatory diet may act synergistically with cigarette smoking and diabetes to increase the risk of PanC beyond the risk of any of these factors alone.

Risk of non-hematologic cancer in individuals with high-count monoclonal B-cell lymphocytosis

It is unknown whether individuals with monoclonal B-cell lymphocytosis (MBL) are at risk for adverse outcomes associated with chronic lymphocytic leukemia (CLL), such as the risk of non-hematologic cancer. We identified all locally residing individuals diagnosed with high-count MBL at Mayo Clinic between 1999 and 2009 and compared their rates of non-hematologic cancer with that of patients with CLL and two control cohorts: general medicine patients and patients who underwent clinical evaluation with flow cytometry but who had no hematologic malignancy. After excluding individuals with prior cancers, there were 107 high-count MBL cases, 132 CLL cases, 589 clinic controls and 482 flow cytometry controls. With 4.6 years median follow-up, 14 (13%) individuals with high-count MBL, 21 (4%) clinic controls (comparison MBL P<0.0001), 18 (4%) flow controls (comparison MBL P=0.0001) and 16 (12%) CLL patients (comparison MBL P=0.82) developed non-hematologic cancer. On multivariable Cox regression analysis, individuals with high-count MBL had higher risk of non-hematologic cancer compared with flow controls (hazard ratio (HR)=2.36; P=0.04) and borderline higher risk compared with clinic controls (HR=2.00; P=0.07). Patients with high-count MBL appear to be at increased risk for non-hematologic cancer, further reinforcing that high-count MBL has a distinct clinical phenotype despite low risk of progression to CLL.