Primary Thromboprophylaxis and the Risk of Venous Thromboembolic Events in Patients With Testicular Germ Cell Tumors Treated With Cisplatinum-Based Chemotherapy.

BACKGROUND: Cisplatinum-based chemotherapy is associated with an increased risk of venous thromboembolism (VTE). We hypothesized that primary thromboprophylaxis in patients with testicular germ cell tumors (GCT) undergoing cisplatinum-based chemotherapy can reduce the risk of VTE. PATIENTS AND METHODS: In this single-center retrospective cohort study, we investigated the increased use of primary thromboprophylaxis between January 2000 and December 2021 at our institution and its effect on the risk of VTE. Patients with GCT undergoing adjuvant or curative cisplatinum-based chemotherapy were included. RESULTS: Three hundred forty-six patients with GCT initiating a cisplatinum-based therapy were included in the study, of whom 122 (35%) were treated in the adjuvant and 224 (65%) in the curative setting, respectively. VTE events occurred in 49 (14.2%) patients. In univariable competing risk analysis, a higher clinical tumor stage and large retroperitoneal lymphadenopathy (RPLND >5 cm) were the strongest predictors of an elevated VTE risk (SHR for stage IIC - IIIC: 2.6 (95%CI: 5.0-24.7, P < .001), SHR for RPLN: 2.36 (95%CI: 1.27-4.4, P < .007)). The proportion of patients receiving primary thromboprophylaxis strongly increased over time and reached 100% in CS IIC-III patients from 2019 onwards. After adjusting for tumor stage, primary thromboprophylaxis was associated with a 52% relatively lower risk of VTE (SHR = 0.48, 95% CI: 0.24-0.97; P = .032). CONCLUSION: In this retrospective cohort study, we showed that TGCT patients undergoing cisplatinum-based chemotherapy have a lower VTE risk when receiving primary thromboprophylaxis. For the duration of chemotherapy, primary thromboprophylaxis should be considered on a risk-benefit ratio.

Production of a mono-biotinylated EGFR nanobody in the E. coli periplasm using the pET22b vector.

OBJECTIVE: Our aim was to produce a mono-biotinylated single domain antibody ('nanobody') specific for the epidermal growth factor receptor (EGFR), which is overexpressed in many cancer cells. The binding of the nanobody and its function are tested in cancer cells. The construct could be used to carry variable therapeutic or diagnostic load using biotin-streptavidin bridging. RESULTS: The EGFR-specific 7D12 nanobody was genetically fused to an IgA hinge linker and to a C-terminal biotin ligase acceptor sequence, allowing mono-biotinylation in E. coli. Expression was in strain BL21-DE3 from a T7 RNA polymerase driven pET22b vector. The biotinylated nanobody, isolated from the periplasm, was purified using streptavidin-mutein affinity chromatography. Final yields were up to 5 mg/l of cell culture. We showed that the construct could bind to EGFR expressing A431 epidermoid carcinoma cells, and to transiently transformed EGFR overexpressing HEK293T cells and not to EGFR negative control cells. The specificity for the EGFR was further demonstrated by immunoprecipitation. To test the functionality, PC9 non-small cell lung cancer cells were treated with mono-biotinylated nanobody or with streptavidin-coupled tetravalent nanobodies. Both were able to block mutant EGFR phosphorylation and slow down growth of PC9 cells. Tetravalent nanobodies were able to downregulate AKT phosphorylation.