[Hereditary colorectal cancer : An update on genetics and entities in terms of differential diagnosis]

The pathologist can contribute to recognizing hereditary causes of colorectal cancer via morphology. By identifying so-called index patients, it is possible to take preventive measures in affected families. The precise definition of the clinical presentation and the histopathological phenotype help to narrow the spectrum of expected genetic alterations. Novelties within Lynch syndrome include the recognition of EPCAM as a fifth gene locus, as well as the newly defined Lynch-like syndrome with evidence of somatic mismatch repair (MMR) mutations. With regard to polyposis-associated syndromes, the spectrum of polyps, whether serrated, hamartomatous or classic adenoma, is of crucial importance. The resulting differential diagnosis includes (attenuated) familial adenomatous polyposis ([a]FAP), MUTYH-associated polyposis (MAP), polymerase proofreading-associated polyposis (PPAP), phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS), Peutz-Jeghers syndrome and juvenile polyposis, each with a specific genetic background.

Large-Deviation Properties of Sequence Alignment of Correlated Sequences

The significance of alignment scores of optimally aligned DNA sequences can be estimated through the score distribution of pairs of random sequences. It is necessary to obtain statistics for the relevant high-scoring tail of the distribution. For local alignments of iid drawn sequences it has already been shown that the often assumed Gumbel distribution does not hold in the distribution tail, but has to be corrected by a Gaussian factor. Real DNA sequences were observed to show long-range correlations within sequences, which are not correctly modeled by iid random sequences. In this publication the large deviation method that was used in previous studies is applied to local and global alignment of such sequences with long-range correlations. We study the distributions over the full range of the support and obtained probabilities as low as [Formula: see text]. We show that again a correction to the Gumbel distribution is necessary to study the dependence of the parameters on the correlation strength. For global alignments the Gamma distribution, which was found heuristically to be a good fit in earlier simple sampling studies, is found to be a poor fit.

Somatosensory profiles of patients with chronic myogenic temporomandibular disorders in relation to their painDETECT score

BACKGROUND

The purpose of this study was to characterize patients with chronic temporomandibular disorders (TMD) in terms of existing hyperalgesia against cold, heat and pressure.

METHODS

The extent of hyperalgesia for pressure and thermal sensation in TMD patients was determined by the use of the painDETECT questionnaire ("Is cold or heat in this area occasionally painful?" "Does slight pressure in this area, e.g., with a finger, trigger pain?") and experimental somatosensory testing against thermal and pressure stimuli (Quantitative Sensory Testing; QST). In addition, we explored psychological comorbidity among the chronic TMD patients (hospital anxiety and depression scale, HADS-D and coping strategies questionnaire, CSQ).

RESULTS

Nineteen patients with chronic TMD and 38 healthy subjects participated in the study. N = 12 patients had a painDETECT score ≤ 12, n = 3 patients had a painDETECT score of 13-18 and n = 4 patients had a painDETECT score ≥ 19. TMD patients with painDETECT scores ≥19 had moderately, strong or very strong enhancement of thermal and pressure pain perception, whereas patients with painDETECT scores 13-18 and ≤ 12 responded these questions with "never", "hardly noticed" or "slightly painful" (p < 0.05-0.01). With increasing painDETECT scores we found increased hyperalgesia for pressure (p < 0.01) and thermal stimuli (p < 0.05) in QST. The patients with a painDETECT score ≥ 19 showed increased signs of anxiety (p < 0.05), depression (p < 0.01), praying and hoping (p < 0.05).

CONCLUSION

The present study has shown that the PainDETECT questionnaire can be a helpful additional diagnostic tool. Together with QST, the PainDETECT questionnaire detected hyperalgesia for pressure and thermal sensation. Therefore the PainDETECT questionnaire is helpful to decide which TMD patients should undergo QST.

Pancreas transplant rejection episodes are not revealed by biopsies of the donor duodenum in a prospective study with paired biopsies

The surgical technique with duodeno-duodenal enteroanastomosis of pancreas transplants allows for representative endoscopic ultrasound-guided needle biopsies of the donor duodenum and the pancreas graft. We assessed whether histological findings in transplanted donor duodenal biopsies can indicate rejection in the transplanted pancreas. Since September 2012, a duodeno-duodenal enteroanastomosis has been the default technique for pancreas transplantations at our center. In 67 recipients we prospectively examined 113 endoscopic ultrasound-guided procedures with representative biopsies from the duodenum grafts and the pancreas grafts (97 per protocol and 16 on indication). All graft biopsies were evaluated according to established rejection criteria. A total of 22 biopsy-proven pancreas rejections were detected, with 2 matching duodenal biopsies showing rejection. This gives a sensitivity of 9% for detection of a pancreas rejection by duodenal biopsies. The other matching duodenal biopsies were either normal (n = 13) or indeterminate (n = 7). Rejection of the donor duodenum was found in only 6/113 biopsies, with 2 concurrent pancreas rejections. In conclusion, the donor duodenum is not a useful reporter organ for rejection in the pancreas graft.

Structural and mechanistic aspects influencing the ADAM10-mediated shedding of the prion protein

Background

Proteolytic processing of the prion protein (PrPC) by endogenous proteases generates bioactive membrane-bound and soluble fragments which may help to explain the pleiotropic roles of this protein in the nervous system and in brain diseases. Shedding of almost full-length PrPC into the extracellular space by the metalloprotease ADAM10 is of peculiar relevance since soluble PrP stimulates axonal outgrowth and is protective in neurodegenerative conditions such as Alzheimer’s and prion disease. However, molecular determinates and mechanisms regulating the shedding of PrP are entirely unknown.

Methods

We produced an antibody recognizing the neo-epitope of shed PrP generated by ADAM10 in biological samples and used it to study structural and mechanistic aspects affecting the shedding. For this, we investigated genetically modified cellular and murine models by biochemical and morphological approaches.

Results

We show that the novel antibody specifically detects shed PrP in cell culture supernatants and murine brain. We demonstrate that ADAM10 is the exclusive sheddase of PrPC in the nervous system and reveal that the glycosylation state and type of membrane-anchorage of PrPC severely affect its shedding. Furthermore, we provide evidence that PrP shedding can be modulated by pharmacological inhibition and stimulation and present data suggesting that shedding is a relevant part of a compensatory network ensuring PrPC homeostasis of the cell.

Conclusions

With the new antibody, our study introduces a new tool to reliably investigate PrP-shedding. In addition, this study provides novel and important insight into the regulation of this cleavage event, which is likely to be relevant for diagnostic and therapeutic approaches even beyond neurodegeneration.

Prognostic Value of Molecular Breast Cancer Subtypes based on Her2, ESR1, PGR and Ki67 mRNA-Expression in Muscle Invasive Bladder Cancer

INTRODUCTION: Gene expression analyses have identified similarities between bladder and breast cancer, where clinical risk stratification is based on Her2, ESR1, PGR and Ki67 expression. The aim of the study was to assess the respective marker gene expression in patients treated with radical cystectomy for muscle-invasive bladder cancer (MIBC) and to evaluate the applicability of breast cancer subtypes for MIBC risk stratification. MATERIALS & METHODS: 102 patients treated with radical cystectomy for MIBC were assessed. Using routine FFPE tissue and an IVD validated kit, mRNA expression was measured by single step RT-qPCR. Partition test were employed to define cut-off values for high or low marker gene expression. Association of expression with outcome was assessed using Kaplan-Meier analysis and multivariate cox regression analysis. Finally, we performed validation of our results in the MD-Anderson cohort (n = 57). RESULTS: Cancer specific survival (CSS) was impaired in patients with high gene expression of Her2 (P = 0.0009) and ESR1 (P = 0.04). In the multivariate regression model Her2 expression remained significant for the prediction of CSS (HR = 2.11, CI 1.11-4.21, P = 0.024). Furthermore, molecular stratification by breast cancer subgroups was significant (P = 0.023) for CSS prediction. Especially the differentiation between Her2-positive and Luminal A (HR = 4.41, CI 1.53-18.71, P = 0.004) and Luminal B (HR = 1.96, CI 0.99-4.08, P = 0.053) respectively was an independent prognostic parameter for CSS. External validation resulted in comparable risk stratification with differences in fractional subgroups distribution. CONCLUSION: Gene expression of Her2, ESR1, PGR, Ki67 and corresponding breast cancer subtypes allow a risk-stratification in MIBC, whereby Her2 overexpressing tumors reveal a particularly poor prognosis.

Abstract P2-09-02: Blinded molecular subtyping analysis from RNA-Seq of FFPE samples in the GeparQuinto trial reveals predictive value of VEGFA metagene for bevacizumab treatment

Background:

RNA-Seq from total RNA in FFPE tissue can be more challenging due to limited capture of partially degraded RNA. Exome-capture based RNA-Seq may circumvent such problems and allow reproducible complete molecular characterization of low-quality RNA from small clinical samples.

Methods:

HER2 negative patients within the GeparQuinto trial were treated with neoadjuvant anthracycline-taxane-based chemotherapy +/- bevacizumab. Patients with bevacizumab therapy had a significantly higher pCR rate, especially within the triple negative subgroup. We performed exome-capture RNA-Seq on 5µm FFPE sections from pre-therapeutic cores of 400 HER2 negative samples from this trial. In a prospectively planned, blinded study we correlated molecular subtypes and metagenes for proliferation, stroma, MHC2, and VEGFA with clinical and histopathological data. Molecular subtypes were defined using the AIMS methods. Metagenes were calculated as mean values corresponding to previously described gene clusters after platform transfer (Rody et al. 2011 PMID 21978456, Hu et al. 2009 PMID 19291283) and then z-transformed.

Results:

296 samples with RNA-Seq data were classified as either of high (n=226) or of limited quality (n=70). For 22 samples RNA yield was insufficient and 82 did not pass initial QC. 121 (41%), 63 (21%), 34 (11.5%), 46 (15.5%), and 32 (11%) samples were defined as basal-like, HER2-enriched, luminal A, luminal B, and normal-like, respectively. Subtyping was robust with regard to gene filtering, normalization, and sample quality. ER and PR status from local IHC strongly correlated with gene expression (overall correctness 84% and 80% for ER, and 85% and 74% for PR, in samples with high and limited quality, respectively) and luminal subtypes (95% ER positive). Proliferation metagene correlated with histological grade (median -0.73, -0.39, and 0.53 in G1, G2, and G3, respectively; P&lt;0.001) and MHC2 metagene correlated strongly with TIL counts (Rho=0.53, P&lt;0.001). Among the high quality samples response rates (49.3% pCR overall) differed significantly by subtype, with higher pCR rates in basal-like (68.9%) and HER2-enriched (45.5%) than in luminal B (35.7%), luminal A (17.9%), and normal-like (20.0%). MHC2- (OR 1.60, 95%CI 1.21-2.12, P=0.001), proliferation- (OR 2.88, 95%CI 2.00-4.16, P&lt;0.001), and VEGFA-metagenes (OR 1.92, 95%CI 1.41-2.60, P&lt;0.001) were significant predictors for pCR. In a multivariate logistic regression (adjusted for bevacizumab treatment and hormone receptor status) both VEGFA metagene (OR 2.59, 95%CI 1.40-4.77, P=0.002) and the interaction between the VEGFA-metagene and bevacizumab treatment arm (P=0.023) significantly predicted pCR.

Conclusions:

Exome-capture RNA-Seq allows robust genomic characterization of clinical samples with limited FFPE material from core biopsies, and molecular subtypes and immune metagenes are predictive for pCR. The VEGFA metagene is a specific predictor for response to neoadjuvant bevacizumab treatment.

Citation Format: Karn T, Meissner T, Weber K, Sinn B, Denkert C, Budczies J, Nekljudova V, Fasching PA, Holtrich U, Schem C, Solbach C, Hartmann A, Röcken C, Untch M, Young BM, Willis S, Leyland-Jones B, von Minckwitz G, Loibl S. Blinded molecular subtyping analysis from RNA-Seq of FFPE samples in the GeparQuinto trial reveals predictive value of VEGFA metagene for bevacizumab treatment [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-02.

SPECT bei reversibler Symptomatik zerebrovaskulärer Erkrankungen

ln 16 patients with reversible symptoms of cerebrovascular disease a HMPAO- and/or IMP-SPECT was performed. 12 of these patients were suffering from TIA, 4 from PRIND. Using HMPAO-SPECT in 8 out of 9 patients with TIA and in 1 of 2 with PRIND a hypoperfusion could be demonstrated; IMP-SPECT showed a pathological pattern in 3 of 5 patients with TIA and in none of 2 patients with PRIND. A semiquantitative evaluation showed a tracer accumulation reduced by 13 ± 12% (HMPAO) and 8 ± 7% (IMP), respectively, in the clinically involved hemisphere, compared to the contralateral side. In circumscript SPECT lesions a reduction by 21 ± 8% (HMPAO) or 17 ± 7% (IMP) was observed. The interhemispheric ratio from the HMPAO-SPECT showed a significant correlation to that of the 133Xe-rCBF measurement (r = 0.86; p <0.001). SPECT was positive in a higher percentage than TCT, Doppler sonography, radioangiography and 133Xe-rCBF measurement. This does not imply a higher specificity or sensitivity, because a slight inhomogenic SPECT pattern may occasionally be observed even in normal persons.

[Diagnostic and predictive molecular pathology of head and neck neoplasms]

As a result of some seminal observations as well as a consequence of increasing use of modern and innovative molecular diagnostic technologies, a variety of new genetic aberrations have been discovered in head and neck neoplasms of different anatomic locations and histogenetic origins. These advances resulted in the establishment of new molecularly defined disease entities. On the other hand, some of these new genetic biomarkers paved the way to potentially promising novel therapeutic opportunities. Diverse old (well known in other entities) and newly discovered translocations and gene fusions represent the leading subgroup of these genetic aberrations. They have been detected not only in malignant epithelial neoplasms (carcinomas) of the salivary glands, but also in carcinomas from other head and neck sites as well as diverse mesenchymal tumors. In addition to these gene fusions, several activating mutations (such as CTNNB1 in sinonasal glomangiopericytoma) as well as inactivating mutations or deletions (like SMARCB1 loss in sinonasal carcinomas) were detected as new molecular markers. In the present review we summarize the relevant molecular alterations in topographically and histopathologically distinct tumors of the head and neck region with emphasis on recently established molecular markers.