Trastuzumab treatment of patients with early, HER2-positive breast cancer in 17 certified German breast cancer centers.

PURPOSE: Since 2008, guidelines recommend that patients with HER2-positive early breast cancer (BC) should receive adjuvant chemotherapy in combination with trastuzumab in Germany. However, recent studies highlight that a substantial share of patients do not receive trastuzumab. We investigate which patient characteristics are associated with a tumor board recommendation for trastuzumab in Breast Cancer Centers (BCC) certified by the German Cancer Society (DKG) and the German Society for Senology, and if the recommendation differs between BCCs. MATERIALS AND METHODS: Multi-level modeling was performed using quality assurance data based on 3052 HER2-positive, operated patients with a first diagnosis of early BC treated between 2006 and 2019 in 17 BCCs in Germany to investigate whether trastuzumab recommendation varies with patient sex, age, and disease characteristics, as well as over time and across BCCs. RESULTS: Tumor board recommendations for trastuzumab differ substantially between BCCs (intraclass correlation coefficient [ICC] null model: 0.11). Our final model (ICC 0.17, Akaike Information Criterion [AIC], 1328.0, R2 0.69) shows that physicians in BCCs more often recommend trastuzumab to patients who are younger than 60 years and those with a recommendation for any additional therapy (chemotherapy, radiation or endocrine therapy) (all p < 0.05). Furthermore, there is a significant time-dependent increase of trastuzumab recommendations (odds ratio [OR] = 1.38, 95% confidence interval [CI] = 1.31-1.46, p < 0.05). CONCLUSION: In certified BCCs in Germany, guideline concordant trastuzumab recommendation is increasing since 2006 (positive cohort effect). Recommendation of trastuzumab for HER2-positive BC patients in BCCs is significantly associated with patients' age and the recommendations for other additional therapy strategies, apart from surgery. The quality assurance data analyzed do not include potentially relevant confounders, such as socioeconomic status or comorbidities.

Use of social service counseling by cancer patients: an analysis of quality assurance data of 6339 breast cancer patients from 13 certified centers in Germany treated between 2015 and 2017.

BACKGROUND: Integrated social care may help to mitigate social risk factors in order to achieve more equitable health outcomes. In cancer centers certified according to the criteria set out by the German Cancer Society, every patient must be given low-threshold access to qualified social workers at the center for in-house social service counseling (SSC). Previous analyses have demonstrated large variation in the utilization of these services across individual centers. Therefore, this research aims at investigating whether SSC utilization varies regarding breast cancer patient characteristics and center characteristics presenting a unique approach of using routine data. METHODS: Multilevel modeling was performed using quality assurance data based on 6339 patients treated in 13 certified breast cancer centers in Germany in order to investigate whether SSC utilization varies with patient sex, age, and disease characteristics as well as over time and across centers. RESULTS: In the sample, 80.3% of the patients used SSC. SSC use varies substantially between centers for the unadjusted model (ICC = 0.24). Use was statistically significantly (P < .001) more likely in women, patients with invasive (in comparison to tumor in situ/ductal carcinoma in situ) diseases (P < .001), patients with both breasts affected (P = .03), patients who received a surgery (P < .001), patients who were diagnosed in 2015 or 2017 compared to 2016 (P < .001) and patients older than 84 years as compared to patients between 55 and 64 years old (P = .002). CONCLUSION: The analysis approach allows a unique insight into the reality of cancer care. Sociodemographic and disease-related patient characteristics were identified to explain SSC use to some extent.

Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction.

Physiological function and pathology of the Alzheimer's disease causing amyloid precursor protein (APP) are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs). The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD) including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR) techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.

LRP1 Modulates APP Intraneuronal Transport and Processing in Its Monomeric and Dimeric State.

The low-density lipoprotein receptor-related protein 1, LRP1, interacts with APP and affects its processing. This is assumed to be mostly caused by the impact of LRP1 on APP endocytosis. More recently, also an interaction of APP and LRP1 early in the secretory pathway was reported whereat retention of LRP1 in the ER leads to decreased APP cell surface levels and in turn, to reduced Aß secretion. Here, we extended the biochemical and immunocytochemical analyses by showing via live cell imaging analyses in primary neurons that LRP1 and APP are transported only partly in common (one third) but to a higher degree in distinct fast axonal transport vesicles. Interestingly, co-expression of LRP1 and APP caused a change of APP transport velocities, indicating that LRP1 recruits APP to a specific type of fast axonal transport vesicles. In contrast lowered levels of LRP1 facilitated APP transport. We further show that monomeric and dimeric APP exhibit similar transport characteristics and that both are affected by LRP1 in a similar way, by slowing down APP anterograde transport and increasing its endocytosis rate. In line with this, a knockout of LRP1 in CHO cells and in primary neurons caused an increase of monomeric and dimeric APP surface localization and in turn accelerated shedding by meprin ß and ADAM10. Notably, a choroid plexus specific LRP1 knockout caused a much higher secretion of sAPP dimers into the cerebrospinal fluid compared to sAPP monomers. Together, our data show that LRP1 functions as a sorting receptor for APP, regulating its cell surface localization and thereby its processing by ADAM10 and meprin ß, with the latter exhibiting a preference for APP in its dimeric state.

APP Protein Family Signaling at the Synapse: Insights from Intracellular APP-Binding Proteins.

Understanding the molecular mechanisms underlying amyloid precursor protein family (APP/APP-like proteins, APLP) function in the nervous system can be achieved by studying the APP/APLP interactome. In this review article, we focused on intracellular APP interacting proteins that bind the YENPTY internalization motif located in the last 15 amino acids of the C-terminal region. These proteins, which include X11/Munc-18-interacting proteins (Mints) and FE65/FE65Ls, represent APP cytosolic binding partners exhibiting different neuronal functions. A comparison of FE65 and APP family member mutant mice revealed a shared function for APP/FE65 protein family members in neurogenesis and neuronal positioning. Accumulating evidence also supports a role for membrane-associated APP/APLP proteins in synapse formation and function. Therefore, it is tempting to speculate that APP/APLP C-terminal interacting proteins transmit APP/APLP-dependent signals at the synapse. Herein, we compare our current knowledge of the synaptic phenotypes of APP/APLP mutant mice with those of mice lacking different APP/APLP interaction partners and discuss the possible downstream effects of APP-dependent FE65/FE65L or X11/Mint signaling on synaptic vesicle release, synaptic morphology and function. Given that the role of X11/Mint proteins at the synapse is well-established, we propose a model highlighting the role of FE65 protein family members for transduction of APP/APLP physiological function at the synapse.

APLP1 Is a Synaptic Cell Adhesion Molecule, Supporting Maintenance of Dendritic Spines and Basal Synaptic Transmission.

The amyloid precursor protein (APP), a key player in Alzheimer's disease, belongs to the family of synaptic adhesion molecules (SAMs) due to its impact on synapse formation and synaptic plasticity. These functions are mediated by both the secreted APP ectodomain that acts as a neurotrophic factor and full-length APP forming trans-cellular dimers. Two homologs of APP exist in mammals: the APP like proteins APLP1 and APLP2, exhibiting functions that partly overlap with those of APP. Here we tested whether APLP1 and APLP2 also show features of SAMs. We found that all three family members were upregulated during postnatal development coinciding with synaptogenesis. We observed presynaptic and postsynaptic localization of all APP family members and could show that heterologous expression of APLP1 or APLP2 in non-neuronal cells induces presynaptic differentiation in contacting axons of cocultured neurons, similar to APP and other SAMs. Moreover, APP/APLPs all bind to synaptic-signaling molecules, such as MINT/X11. Furthermore, we report that aged APLP1 knock-out mice show impaired basal transmission and a reduced mEPSC frequency, likely resulting from reduced spine density. This demonstrates an essential nonredundant function of APLP1 at the synapse. Compared to APP, APLP1 exhibits increased trans-cellular binding and elevated cell-surface levels due to reduced endocytosis. In conclusion, our results establish that APLPs show typical features of SAMs and indicate that increased surface expression, as observed for APLP1, is essential for proper synapse formation in vitro and synapse maintenance in vivoSIGNIFICANCE STATEMENT According to the amyloid-cascade hypothesis, Alzheimer's disease is caused by the accumulation of Aß peptides derived from sequential cleavage of the amyloid precursor protein (APP) by ß-site APP cleaving enzyme 1 (BACE1) and γ-secretase. Here we show that all mammalian APP family members (APP, APLP1, and APLP2) exhibit synaptogenic activity, involving trans-synaptic dimerization, similar to other synaptic cell adhesion molecules, such as Neuroligin/Neurexin. Importantly, our study revealed that the loss of APLP1, which is one of the major substrates of BACE1, causes reduced spine density in aged mice. Because some therapeutic interventions target APP processing (e.g., BACE inhibitors), those strategies may alter APP/APLP physiological function. This should be taken into account for the development of pharmaceutical treatments of Alzheimer's disease.

Tumour stage distribution and survival of malignant melanoma in Germany 2002-2011.

BACKGROUND: Over the past two decades, there has been a rising trend in malignant melanoma incidence worldwide. In 2008, Germany introduced a nationwide skin cancer screening program starting at age 35. The aims of this study were to analyse the distribution of malignant melanoma tumour stages over time, as well as demographic and regional differences in stage distribution and survival of melanoma patients. METHODS: Pooled data from 61 895 malignant melanoma patients diagnosed between 2002 and 2011 and documented in 28 German population-based and hospital-based clinical cancer registries were analysed using descriptive methods, joinpoint regression, logistic regression and relative survival. RESULTS: The number of annually documented cases increased by 53.2% between 2002 (N = 4 779) and 2011 (N = 7 320). There was a statistically significant continuous positive trend in the proportion of stage UICC I cases diagnosed between 2002 and 2011, compared to a negative trend for stage UICC II. No trends were found for stages UICC III and IV respectively. Age (OR 0.97, 95% CI 0.97-0.97), sex (OR 1.18, 95% CI 1.11-1.25), date of diagnosis (OR 1.05, 95% CI 1.04-1.06), 'diagnosis during screening' (OR 3.24, 95% CI 2.50-4.19) and place of residence (OR 1.23, 95% CI 1.16-1.30) had a statistically significant influence on the tumour stage at diagnosis. The overall 5-year relative survival for invasive cases was 83.4% (95% CI 82.8-83.9%). CONCLUSIONS: No distinct changes in the distribution of malignant melanoma tumour stages among those aged 35 and older were seen that could be directly attributed to the introduction of skin cancer screening in 2008.

FE65 and FE65L1 share common synaptic functions and genetically interact with the APP family in neuromuscular junction formation.

The FE65 adaptor proteins (FE65, FE65L1 and FE65L2) bind proteins that function in diverse cellular pathways and are essential for specific biological processes. Mice lacking both FE65 and FE65L1 exhibit ectopic neuronal positioning in the cortex and muscle weakness. p97FE65-KO mice, expressing a shorter FE65 isoform able to bind amyloid precursor protein family members (APP, APLP1, APLP2), develop defective long-term potentiation (LTP) and aged mice display spatial learning and memory deficits that are absent from young mice. Here, we examined the central and peripheral nervous systems of FE65-KO, FE65L1-KO and FE65/FE65L1-DKO mice. We find spatial learning and memory deficits in FE65-KO and FE65L1-KO mice. Severe motor impairments, anxiety, hippocampal LTP deficits and neuromuscular junction (NMJ) abnormalities, characterized by decreased size and reduced apposition of pre- and postsynaptic sites, are observed in FE65/FE65L1-DKO mice. As their NMJ deficits resemble those of mutant APP/APLP2-DKO mice lacking the FE65/FE65L1 binding site, the NMJs of APLP2/FE65-DKO and APLP2/FE65L1-DKO mice were analyzed. NMJ deficits are aggravated in these mice when compared to single FE65- and FE65L1-KO mice. Together, our data demonstrate a role for FE65 proteins at central and peripheral synapses possibly occurring downstream of cell surface-associated APP/APLPs.