Activation of Myc triggers a rapid induction of cyclin E/ cdk2 kinase activity and degradation of p27. Overt degradation of p27 is preceded by a speci®c dissociation of p27 from cyclin E/cdk2, but not from cyclin D/cdk4 complexes. We now show that cyclin E/cdk2 phosphorylates p27 at a carboxy-terminal threonine residue (T187) in vitro; mutation of this residue to valine stabilises cyclin E/cdk2 complexes. This reaction is not signi®cantly inhibited by high concentrations of p27, suggesting that cdk2 bound to p27 is catalytically active. In vivo, p27 bound to cyclins E and A, but not to D-type cyclins is phosphorylated. Myc-induced release of p27 from cdk2 requires cdk2 kinase activity and is delayed in a T187V mutant of p27. After induction of Myc, p27 phosphorylated at threonine 187 transiently accumulates in a non cdk2 bound form. Our data suggest a mechanism in which p27 is released from cyclin E/cdk2 upon phosphorylation; in Myc-transformed cells, release is e cient as phosphorylated p27 is transiently bound in a non-cdk2 containing complex and subsequently degraded.

Pelvic bone metastases are a growing concern in the field of orthopedic surgery. Patients with pelvic metastasis are individually different with different needs of treatment in order to attain the best possible quality of life despite the advanced stage of disease. A holistic collaboration among the oncologist, radiation therapist, and orthopedic surgeon is mandatory. Special attention has to be directed to osteolytic lesions in the periacetabular region as they can provoke pathological fractures and subsequent functional impairment. Different reconstruction techniques for the pelvis are available; the choice depends on the patient's prognosis, size of the bone defect, and response of the tumor to adjuvant treatment. If all the conservative treatments are exhausted and the patient is not eligible for surgery, one of the various percutaneous ablation procedures can be considered. We propose a pelvic analogue to the treatment algorithm in long bone metastasis and a scoring system in pelvic metastasis. This algorithm aims to simplify the teamwork and to avoid under- or overtreatment of pelvic bone metastases.

BackgroundThe RANK ligand inhibitor denosumab is being investigated for treatment of giant cell tumor of bone, but the available data in the literature remains sparse and controversial. This study analyzes the results of combining denosumab with surgical treatment and highlights possible changes for the oncologic surgeon in daily practice.MethodsA total of 91 patients were treated surgically for giant cell tumor of bone between 2010 and 2014 in an institution, whereas 25 patients of the total additionally received denosumab and were part of this study. The average age of the patients was 35 years. Eleven patients received denosumab pre- and postoperatively, whereas with 14 patients, the denosumab treatment was applied either before (7 patients) or after (7 patients) the surgery. The average preoperative therapy duration was 3.9 months and the postoperative therapy 6 months by default.ResultsSixteen patients presented a large tumor extension necessitating a resection of the involved bone or joint. In 10 of these patients, the indication for a resection procedure was abandoned due to the preoperative denosumab treatment and a curettage was performed. In the remaining six cases, the surgical indication was not changed despite the denosumab treatment, and two of them needed a joint replacement after the tumor resection. Also with patients treated with curettage, denosumab seems to facilitate the procedure as a new peripheral bone rim around the tumor was built, though a histologic analysis reveals viable tumor cells persisting in the denosumab-induced bone formation.After an average follow-up of 23 months, one histologically proven local recurrence occurred, necessitating a second curettage. A second patient showed a lesion in the postoperative imaging highly suspicious for local relapse which remained stable under further denosumab treatment. No adverse effect of the denosumab medication was observed in this study.ConclusionsDenosumab can be a help to the oncologic surgeon by reconstituting a peripheral rim and switching the stage from aggressive to active or latent disease. But as tumor cells remain in the new-formed bone, the surgical technique of curettage has to be changed from gentle to more aggressive to avoid higher local recurrence rates.

This prospective study showed significantly superior outcomes in all clinical scores between GII and GI. The subanalysis of the high-grade injury type (Rockwood IV/V) revealed that these patients showed significant benefits from the dDBS procedure in the clinical assessments. The cHP procedure resulted in good to excellent clinical outcome data and displayed an alternative procedure for patients needing less restrictive rehabilitation protocols.