Neoadjuvant (preoperative) chemoradiotherapy of advanced rectal tumors / Elorehaladott végbéldaganatok neoadjuváns (preoperatív) kemoradioterápiája

Introduction: There have been significant changes in the treatment protocol for rectal tumors in recent decades, greatly reducing the rate of local recurrence and distant metastasis, thereby increasing overall survival. Method: We performed a retrospective processing and statistical analysis of the data of 362 patients with rectal cancer who underwent local neoadjuvant chemoradiotherapy and then underwent surgical treatment between 1 January 2010 and 31 December 2017 at the Institute of Surgery of the University of Debrecen. We compared the response rate and overall survival results of our patients with local neoadjuvant treatment to the outcomes of total neoadjuvant treatment reported by the recent large international studies. Results: We experienced complete pathological regression in 8.6% of our patients. After neoadjuvant therapy, 10.7% of our patients experienced distant metastasis at the time of the operation or within 3 months period thereafter. In our study, the rate of response to the neoadjuvant treatment was a prognostic factor independent of the stage at di-agnosis and recognition. The groups with better response produced significantly better survival results. Conclusion: The total neoadjuvant treatment doubled the number of patients with complete pathological response, and the incidence of distant metastasis was by 7% lower in both recent international studies compared to the local neoadjuvant group. 85% of our patients were T3-4N+ stage at the time of recognition. Given the 10.7% rate of dis- tant metastases detected at the time of surgery or within 3 months in our patient population, we can state that ap- proximately half of our patients would have benefited from the administration of total neoadjuvant therapy which produced better outcomes. Based on this conclusion, we decided to introduce the total neoadjuvant therapy protocol in our department for treatment of patients with advanced rectal tumors.

T-cell Receptor Is a Threshold Detector: Sub- and Supra-Threshold Stochastic Resonance in TCR-MHC Clusters on the Cell Surface.

Stochastic resonance in clusters of major histocompatibility molecules is extended by a more detailed description of adaptive thresholding and by applying the notion of suprathreshold stochastic resonance as a stochastically quantizing encoder of transmembrane signaling downstream of major histocompatibility molecules and T-cell receptors on the side of presenting and recognizing cells, respectively. The adaptive nature of thresholding is partly explained by a mirroring of the noncognate-cognate dichotomy shown by the T-cell receptor structure and the kinetic-segregation model of the onset of T-cell receptor triggering. Membrane clusters of major histocompatibility molecules and T-cell receptors on their host cells are envisioned as places of the temporal encoding of downstream signals via the suprathreshold stochastic resonance process. The ways of optimization of molecular prostheses, such as chimeric antigen receptors against cancer in transmembrane signaling, are suggested in the framework of suprathreshold stochastic resonance. The analogy between Förster resonance energy transfer and suprathreshold stochastic resonance for information transfer is also discussed. The overlap integral for energy transfer parallels the mutual information transferred by suprathreshold stochastic resonance.

Quadruplicate Synchronous Adenocarcinoma of the Colon with Distant Metastases-Long-Term Molecular Follow-Up by KRAS and TP53 Mutational Profiling.

Anatomically independent tumor foci represent biologically distinct neoplasias, potentially featured by different progressivity and treatment responsiveness. To demonstrate the biological complexity, a metastatic colon adenocarcinoma patient originally presenting with four independent primary tumors of the right colon half and altogether eight distant metastases was followed by molecular testing. Next-generation sequencing results highlighted the mutational profile of the individual primaries and the dynamics of the different gene variants observed during follow-up. The four primary colon tumors presented with four different KRAS genotypes, one of them with a wild-type and three with pathogenic variants, without overlap. These were the following: c.35G > A; p.Gly12Asp with 40.6% variant allele frequency (VAF); c.34G > T; p.Gly12Cys with 16.2% VAF and c.35G > T; p.Gly12Val with 15.1% VAF. In metastatic tumors, with one exception where no mutation was detected, only the KRAS c.34G > T; p.Gly12Cys mutation could be detected. TP53 gene variants were variable in the primary tumors, with a single dominant variant evolving in the follow-up metastases (c.820G > T; p.Val274Phe). Genetic profiling of individually developing synchronous malignancies uncovers the clonal relations of metastatic tumors. NGS gene panels provide a solution to follow the dynamics of key oncogene variants during the course of the disease and greatly contribute to therapy optimization.

Correction: Identification of Novel Pathogenic Sequence Variants of the Mismatch Repair Genes During Screening for Lynch Syndrome in a Single Centre of Eastern Hungary.

The original version of this article unfortunately contained a mistake. The variants listed in Table 3 of the original version of this article are not in line with the latest HGVS (Human Genome Variation Society) nomenclature (version 19.01).

Identification of Novel Pathogenic Sequence Variants of the Mismatch Repair Genes During Screening for Lynch Syndrome in a Single Centre of Eastern Hungary.

INTRODUCTION: Lynch syndrome is an autosomal dominant disorder, most frequent leading to colon cancer. Identification of patients with Lynch syndrome and screening of their family members are available prevention approach that can significantly decrease mortality. Unfortunately, routine screening still does not belong to standard of care in Hungary. In this study, we performed a comprehensive screening in order to identify patients with mismatch repair (MMR) mutation between the years of 2011 and 2014. Identified mutations were compared with those already published in the international databases. PATIENTS AND METHODS: Patients who underwent treatment for colorectal cancer at the Surgical Institute of the University of Debrecen were screened using the modified Amsterdam and Bethesda Criteria. Immunohistochemistry and microsatellite analyses were performed in order to identify possible mutation carrier cases. Suspicious cases underwent DNA sequencing to detect mutations in the mismatch repair genes (hMLH1, hMSH2). RESULTS: All together 760 colorectal cancer patients were screened. A total of 28 patients were identified as possible MMR mutation carrier and underwent further genetic evaluation. Pathogenic sequence variants of the MMR gene were found in 5 patients. Hypermethylation of the promoter region of the hMLH1 gene was identified in 2 patients. Two out of the 5 pathogenic sequence variants of the MMR gene were first identified by our group while other 2 mutations were previously published as possible founder mutations. CONCLUSION: Identification of families with Lynch syndrome, while challenging because of variable phenotypes at diagnosis, is feasible with available molecular biological technologies and crucial to reduce mortality caused by this syndrome.

Adaptive threshold-stochastic resonance (AT-SR) in MHC clusters on the cell surface.

Highly conserved 2D receptor clusters (membrane rafts) of immunological signaling molecules with MHCI and MHCII antigens as their cores have been observed in the past on the surface of T- and B-cell lines of lymphoid origin, as well as on cells from patients with colon tumor and Crohn's disease. Conservativity is related to the ever presence of MHCI molecules. Although they are suspected to play a role in maintaining these clusters and facilitating transmembrane signaling, their exact role has been left largely enigmatic. Here we are suggesting stochastic resonance (SR), or "noise-assisted signal detection", as a general organizing principle for transmembrane signaling events evoked by processes like immune recognition and cytokine binding taking place in these clusters. In the conceptual framework of SR, in immune recognition as a prototype of transmembrane signaling, the sea of self-peptide-MHC complexes around a nonself-peptide presenting MHC is conceived as a source of quickly fluctuating unspecific signal ("athermal noise") serving the extra energy for amplifying the weak sub-threshold specific signal of the nonself-peptide presenting MHC. This same noise is also utilized for a readjustment of the threshold - and also the sensitivity and specificity - of detection by a closed loop feedback control of the TcR-CD8 (CD4) proximity on the detecting T-cell. The weak sub threshold specific signal of nonself-peptide presenting MHC is amplified by the superposing unspecific signals of the neighboring self peptide-MHC complexes towards the T-cell receptor as the detector. Because in a successful detection event both self- and nonself-peptides are detected simultaneously, the principle of coincidence (or lock-in) detection is also realized. The ever presence of MHC islands gets a natural explanation as a source of extra power - in a form of "athermal noise" - needed for coincidence detection and frequency encoding the evoked downstream signals. The effect is quite general, because the actual type of molecules surrounding a chief signaling molecule - like nonself-peptide holding MHC, interleukin-2 and -15 cytokine receptors (IL-2R/15R) - as the fluctuating interaction energy sources is immaterial. The model applies also for other types of signaling, such as those evoked by cytokine binding. The phenomenon of SR can also be interpreted as sampling of a low frequency, specific signal with a high frequency unspecific signal, the "noise". Recipes for identifying other forms of SR in membrane clusters with biophysical tools are recommended.

[Open transgastric necrosectomy for extended walled-off pancreas necrosis]. / Kiterjedt, demarkált pancreas necrosis sebészi kezelése transgastricus necrectomiával.

AIMS: In severe acute pancreatitis the timing of necrosectomy is ideally should be postponed 4-6 weeks after the onset of the disease when the walled-of pancreatic necrosis (WOPN) has developed. The authors present their experience with open transgastric necrosectomy for extended WOPN. PATIENTS AND METHODS: The authors performed 17 (12 male, 5 female with a mean age of 61.6 ± 15.1 years) open transgastric necrosectomies for extended WOPN in a period of 1, January 2012 and 31, December 2017. Before the operations conservative and semiconservative therapy was used for an average of 74.6 ± 83.1 days. The mean size of the WOPNs was 13.8 ± 5.2 cm with localisation of the retrocolic and retroduodenal regions. All necroses were septic. RESULTS: Complications related to the operation were not observed. The mean time of hospitalization after the surgery was 11.6 ± 12.8 days. The mortality rate was 5.9%. Late operation or other interventions for pseudocyst or pancreas fistula formation was not performed. Two patients needed endoscopic dilatation with lavage in the early postoperative period because of fever. New diabetes mellitus was not observed but worsening of previously existed diabetes developed in 6.3% of the cases. CONCLUSIONS: The open transgastric necrosectomy is safe and effective for extended WOPN. The advantage of this type of necrosectomy is the prevention of pancreatic pseudocyst and fistula formation.

Hydatid disease of pancreas: A case report.

Primary pancreatic hydatid disease is extremely rare. Diagnosis of the disease is difficult because hydatid cysts can be confused with a pseudocyst or neoplastic cystic diseases. Authors report a case of a surgically treated hydatid disease of the uncinate process of pancreas. In a 34-year-old patient with minor symptoms, a cystic disease of the pancreas was accidentally identified. CT scan revealed a multivesicular cystic mass with a maximum of 13-cm diameter and with a calcificated wall. During laparotomy, the uncinate process of pancreas was resecated and the cystic lesion was enucleated. Patient was recovered without complications and recurrence of the disease. There must be a suspicion of hydatid disease when cysts are identified in good conditioned, asymptomatic patients, or in case of wall calcification or multivesicular cysts revealed by radiological images. Surgical procedures are recommended in uncertain diagnoses too, because differentiation preoperatively between cystic pancreatic lesions is often impossible.

Dual-Laser Tetra-Polarization FRET (4polFRET) for Site-Selective Control of Homo-FRET in Hetero-FRET Systems on the Cell Surface: The Homo-FRET Gate.

The effects of donor homo-Förster resonance energy transfer (homo-FRET) taking place in hetero-FRET systems is described in the context of hetero-FRET detection via donor and acceptor fluorescence anisotropies in cell surface receptor clusters. Donor homo-FRET can influence both the efficiency of detection as well as the magnitude of the detectable hetero-FRET. A 4-fold polarized FRET detection scheme-tetrapolarization FRET (4polFRET)-is proposed not only for discriminating the effects of homo-FRET from those of hetero-FRET, but also for correlating homo-associations of the donors and acceptors at different donor-acceptor distances, even beyond the critical Förster distance for hetero-FRET ( R0). The method is based on suppressing homo-FRET at the donor side with red-edge excitation. After the anisotropy effects of physical rotation and homo-FRET were separated by site-selective spectroscopy, the magnitude of the effect of homo-FRET on hetero-FRET has been estimated. It has been found significant, offering a new sensitive technique for detecting conformational dynamics via the homo-FRET mediated component of hetero-FRET, the "homo-FRET enhanced hetero-FRET" or "homo-FRET gate". The method is realizable in flow, as well as in image cytometry equipped with polarization detecting facility.

Checkpoint for helicity conservation in fluorescence at the nanoscale: Energy and helicity transfer (hFRET) from a rotating donor dipole.

Orientation factor (κ2) for FRET from a rotating donor dipole, transferred helicity of the donor field and torque exerted on the acceptor by the donor have been investigated in the framework of classical electrodynamics. It is shown that for rotating dipole, κ2 is significantly higher as compared to linear dipole independently of the orientation distribution of the donor and acceptor and whether the static or the dynamic rotational regimes are used for averaging κ2. By this property of κ2, FRET serves as an example for a phenomenon where local field interference may take place in a "natural" way for emitters possessing rotating dipoles in their excited states by nature. The overlapping spatial distributions for the helicity of donor local field, torque exerted on the acceptor by the donor and for the FRET orientational factor suggest that transfer of both energy and helicity take place predominantly in the plane of rotation by keeping the original direction of helicity, i.e. in accordance with the conservation law for helicity. Orienting FRET has been proposed by engineering local field structure by using elliptically polarized light for donor excitation or by using linearly polarized light coupled with electromagnetic modification of the donor environment. The phenomenon of increased κ2 can be exploited for checking helicity conservation for different FRET donors without the need for polarized detection optics. Modulation of FRET with changing ellipticity of the excited donor state might supply structural and dynamical information on the orientational distribution of dye-holding matrices even on the surface of living cells, e.g. on the level of cell surface receptor clusters. Furthermore, it might also be exploited in sensing local electromagnetic fields. Rotating excited donor states might also facilitate turning on photoswitchable acceptors.

Confocal microscopic dual-laser dual-polarization FRET (2polFRET) at the acceptor side for correlating rotations at different distances on the cell surface.

Relationship of donor and acceptor fluorescence anisotropies as well as efficiency of fluorescence resonance energy transfer (FRET) has been investigated in a confocal microscope in the context of FRET systems comprised of donor and acceptor-labeled MHCI and MHCII receptors on the surface of Kit-225 K6 human T-cells. The measurements have been carried out in a 2-laser, 5-signal platform where the total donor fluorescence intensity and 2 acceptor fluorescence intensities with their anisotropies - one at the donor's excitation wavelength, the other at the acceptor's excitation wavelength - have been detected. This configuration enabled the determination of FRET efficiency and correlating it with the two acceptor fluorescence anisotropies as a kind of calibration. Estimations for the FRET-enhanced donor fluorescence anisotropy, the directly excited acceptor fluorescence anisotropy, and the fluorescence anisotropy of sensitized emission have been obtained. Procedures for determining FRET by measuring only the total donor intensity and the acceptor intensity and its anisotropy, or two acceptor intensities and their anisotropies have been elaborated, the errors of which have been estimated based on the fluorescence anisotropy values obtained in the calibration with the method of flow cytometric energy transfer (FCET). The combined detection of the donor and acceptor fluorescence anisotropies enabled also the determination of the lower and upper limits of the orientation factor for FRET (κ2). An increase in range for κ2 with increasing FRET efficiency has been observed, with average κ2 values different from the dynamic random average of 2/3. These observations call for the need of κ2 determination in proximity measurements, where the donor and acceptor orientations are not predictable. An increasing range of κ2 with increasing intermolecular proximity of the MHCI and MHCII receptors has been observed. This indicates that molecular flexibility in the clusters of the MHCI and MHCII receptors reduces with increasing cluster density, i.e. a "fluidity gradient" exists in the clusters. More specifically, the local density dependent flexibility can also be taken as a direct proof for that the association of these receptors is non-random, but mediated by some type of physical interaction, a finding as a benefit of FRET detection by polarization spectroscopy. Two new quantities - the quenched donor fluorescence anisotropy and a fluorescence anisotropy analogue, the "dissymmetry index" of the polarized FRET efficiency components - have also been introduced for the characterization of the orientational dynamics of the excited state during FRET.