Beta2-microglobulin mutations in microsatellite unstable colorectal tumors

Defects of DNA mismatch repair (MMR) cause the high level microsatellite instability (MSI-H) phenotype. MSI-H cancers may develop either sporadically or in the context of the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome that is caused by germline mutations of MMR genes. In colorectal cancer (CRC), MSI-H is characterized by a dense lymphocytic infiltration, reflecting a high immunogenicity of these cancers. As a consequence of immunoselection, MSI-H CRCs frequently display a loss of human leukocyte antigen (HLA) class I antigen presentation caused by mutations of the beta2-microglobulin (beta2m) gene. To examine the implications of beta2m mutations during MSI-H colorectal tumor development, we analyzed the prevalence of beta2m mutations in MSI-H colorectal adenomas (n=38) and carcinomas (n=104) of different stages. Mutations were observed in 6/38 (15.8%) MSI-H adenomas and 29/104 (27.9%) MSI-H CRCs. A higher frequency of beta2m mutations was observed in MSI-H CRC patients with germline mutations of MMR genes MLH1 or MSH2 (36.4%) compared with patients without germline mutations (15.4%). The high frequency of beta2m mutations in HNPCC-associated MSI-H CRCs is in line with the hypothesis that immunoselection may be particularly pronounced in HNPCC patients with inherited predisposition to develop MSI-H cancers. beta2m mutations were positively related to stage in tumors without distant metastases (UICC I-III), suggesting that loss of beta2m expression may promote local progression of colorectal MSI-H tumors. However, no beta2m mutations were observed in metastasized CRCs (UICC stage IV, p=0.04). These results suggest that functional beta2m may be necessary for distant metastasis formation in CRC patients.     

Rationale, design, and methods for the risk evaluation and communication health outcomes and utilization trial (REACH OUT)

OBJECTIVE: To test the primary study hypothesis that a physician-delivered coronary heart disease risk evaluation and communication program can lower patients' predicted 10-year risk of myocardial infarction or death due to coronary heart disease by 10% within 6 months compared to usual care. DESIGN: Prospective, parallel group, open-label, controlled, cluster-randomized multinational trial; the study site is the unit of randomization. SETTING: Patients were recruited from 106 general practices located in nine European countries. PATIENTS: Men and women aged 45 to 64 (N=1500) with a documented history of hypertension (treated or untreated), systolic blood pressure > or =140 mmHg (or > or =130 mmHg in the presence of renal or kidney disease), no history of cardiovascular disease, and a predicted 10-year risk of myocardial infarction or death due to coronary heart disease > or =10%. INTERVENTION: Sites were randomized to deliver a physician-directed coronary heart disease risk communication and education program or usual care. The intervention program included informing patients of their 10-year risk of myocardial infarction or death due to coronary heart disease, educating patients about modifiable risk factors and their control, and three follow-up phone calls by a physician or study nurse. MAIN OUTCOME MEASURE: Predicted 10-year risk of myocardial infarction or death due to coronary heart disease at 6 months. CONCLUSIONS: REACH OUT will evaluate a novel, patient-focused, physician-implemented application of coronary heart disease risk equations. Results of the study will be of practical relevance to physicians, health care organizations, and those who issue clinical guidelines for the reduction of cardiovascular risk.     

Successful collection of peripheral blood progenitor cells in patients with acute myeloid leukaemia following early consolidation therapy with granulocyte colony-stimulating factor-supported high-dose cytarabine and mitoxantrone

We evaluated the feasibility of collecting peripheral blood progenitor cells (PBPC) in patients with acute myeloid leukaemia (AML) following two cycles of induction chemotherapy with idarubicin, cytarabine and etoposide (ICE), and one cycle of consolidation therapy with high-dose cytarabine and mitoxantrone (HAM). Thirty-six patients of the multicentre treatment trial AML HD93 were enrolled in this study, and a sufficient number of PBPC was harvested in 30 (83%). Individual peak concentrations of CD34⁺ cells in the blood varied (range 13.1–291.5/μl; median 20.0/μl). To reach the target quantity of 2.5 × 10⁶ CD34⁺ cells/kg, between one and six (median two) leukaphereses (LP) were performed. The LP products contained between 0.2 × 10⁶ and 18.9 × 10⁶ CD34⁺cells/kg (median 1.2 × 10⁶/kg). Multivariate analysis showed that the white blood cell count prior to HAM and the time interval from the start of HAM therapy to reach an unsupported platelet count > 20 × 10⁹/l were predictive for the peak value of CD34⁺ cells in the blood during the G-CSF stimulated haematological recovery. In 16 patients an intraindividual comparison was made between bone marrow (BM) and PBPC grafts. Compared to BM grafts, PBPC grafts contained 14-fold more MNC, 5-fold more CD34⁺ cells and 36-fold more CFU-GM. A CD34⁺ subset analysis showed that blood-derived CD34⁺ cells had a more immature phenotype as indicated by a lower mean fluorescence intensity for HLA-DR and CD38. In addition, the proportion of CD34⁺/Thy-1⁺ cells tended to be greater in the PBPC grafts. The data indicate that sufficient PBPC can be collected in the majority of patients with AML following intensive double induction and first consolidation therapy with high-dose cytarabine and mitoxantrone.     

Targeting the spliceosome in chronic lymphocytic leukemia with the macrolides FD-895 and pladienolide-B

RNA splicing plays a fundamental role in human biology. Its relevance in cancer is rapidly emerging as demonstrated by spliceosome mutations that determine the prognosis of patients with hematologic malignancies. We report studies using FD-895 and pladienolide-B in primary leukemia cells derived from patients with chronic lymphocytic leukemia and leukemia-lymphoma cell lines. We found that FD-895 and pladienolide-B induce an early pattern of mRNA intron retention – spliceosome modulation. This process was associated with apoptosis preferentially in cancer cells as compared to normal lymphocytes. The pro-apoptotic activity of these compounds was observed regardless of poor prognostic factors such as Del(17p), TP53 or SF3B1 mutations and was able to overcome the protective effect of culture conditions that resemble the tumor microenvironment. In addition, the activity of these compounds was observed not only in vitro but also in vivo using the A20 lymphoma murine model. Overall, these findings give evidence for the first time that spliceosome modulation is a valid target in chronic lymphocytic leukemia and provide an additional rationale for the development of spliceosome modulators for cancer therapy.