Malignant transformation of Slp65-deficient pre-B cells involves disruption of the Arf-Mdm2-p53 tumor suppressor pathway

The adapter protein Slp65 is a key component of the precursor-B (pre-B) cell receptor. Slp65-deficient mice spontaneously develop pre-B cell leukemia, but the mechanism by which Slp65-/- pre-B cells become malignant is unknown. Loss of Btk, a Tec-family kinase that cooperates with Slp65 as a tumor suppressor, synergizes with deregulation of the c-Myc oncogene during lymphoma formation. Here, we report that the presence of the immunoglobulin heavy chain transgene VH81X prevented tumor development in Btk -/-Slp65-/- mice. This finding paralleled the reported effect of a human immunoglobulin heavy chain transgene on lymphoma development in Eμ-myc mice, expressing transgenic c-Myc. Because activation of c-Myc strongly selects for spontaneous inactivation of the p19Arf-Mdm2-p53 tumor suppressor pathway, we investigated whether disruption of this pathway is a common alteration in Slp65-/- pre-B cell tumors. We found that combined loss of Slp65 and p53 in mice transformed pre-B cells very efficiently. Aberrations in p19Arf, Mdm2, or p53 expression were found in all Slp65-/-(n = 17)andBtk-/-Slp65-/-(n = 32) pre-B cell leukemias analyzed. In addition, 9 of 10 p53-/-Slp65 -/- pre-B cell leukemias manifested significant Mdm2 protein expression. These data indicate that malignant transformation of Slp65 -/- pre-B cells involves disruption of the p19Arf-Mdm2-p53 tumor suppressor pathway

Postoperative outcomes of primary and interval cytoreductive surgery for advanced ovarian cancer registered in the Dutch Gynecological Oncology Audit (DGOA)

Objectives: The challenge when performing cytoreductive surgery (CRS) is to balance the benefits and risks. The aim of this study was to report short term postoperative morbidity and mortality in relation to surgical outcome in patients undergoing primary debulking surgery (PDS) or interval debulking (IDS) surgery in the Netherlands. Methods: The Dutch Gynecological Oncology Audit (DGOA) was used for retrospective analysis. Patients undergoing PDS or IDS between January 1st, 2015 - December 31st, 2018 were included. Outcome was frequency of postoperative complications. Median time to adjuvant chemotherapy and severity of complications were related to outcome of CRS. Complications with Clavien-Dindo ≥3 were analyzed per region and case mix corrected. Statistical analysis was performed with R.Studio. Results: 1027 patients with PDS and 1355 patients with IDS were included. Complications with re-invention were significantly higher in PDS compared to IDS (5.7% vs. 3.6%, p = 0.048). Complete cytoreduction was 69.7% in PDS and 62.1% IDS, p &lt; 0.001. Time to adjuvant chemotherapy was 49 days in patients with complete CRS and a complication with re-intervention. Regional variation for severe complications showed one region outside confidence intervals. Conclusions: Higher complete cytoreduction rate in the PDS group indicates that the correct patients have been selected, but is associated with a higher percentage of complication with re-intervention. As result, time to start adjuvant chemotherapy is longer in this group. Maintaining a balance in aggressiveness of surgery and outcome of the surgical procedure with respect to severe complications is underlined. Bench marked data should be discussed nationally to improve this balance.</p