A Randomized Trial of Valganciclovir Prophylaxis Versus Preemptive Therapy in Kidney Transplant Recipients.

SIGNIFICANCE STATEMENT: Although cytomegalovirus (CMV) infection is an important factor in the pathogenesis of kidney allograft rejection, previous studies have not determined the optimal CMV prevention strategy to avoid indirect effects of the virus. In this randomized trial involving 140 kidney transplant recipients, incidence of acute rejection at 12 months was not lower with valganciclovir prophylaxis (for at least 3 months) compared with preemptive therapy initiated after detection of CMV DNA in whole blood. However, prophylaxis was associated with a lower risk of subclinical rejection at 3 months. Although both regimens were effective in preventing CMV disease, the incidence of CMV DNAemia (including episodes with higher viral loads) was significantly higher with preemptive therapy. Further research with long-term follow-up is warranted to better compare the two approaches. BACKGROUND: The optimal regimen for preventing cytomegalovirus (CMV) infection in kidney transplant recipients, primarily in reducing indirect CMV effects, has not been defined. METHODS: This open-label, single-center, randomized clinical trial of valganciclovir prophylaxis versus preemptive therapy included kidney transplant recipients recruited between June 2013 and May 2018. After excluding CMV-seronegative recipients with transplants from seronegative donors, we randomized 140 participants 1:1 to receive valganciclovir prophylaxis (900 mg, daily for 3 or 6 months for CMV-seronegative recipients who received a kidney from a CMV-seropositive donor) or preemptive therapy (valganciclovir, 900 mg, twice daily) that was initiated after detection of CMV DNA in whole blood (≥1000 IU/ml) and stopped after two consecutive negative tests (preemptive therapy patients received weekly CMV PCR tests for 4 months). The primary outcome was the incidence of biopsy-confirmed acute rejection at 12 months. Key secondary outcomes included subclinical rejection, CMV disease and DNAemia, and neutropenia. RESULTS: The incidence of acute rejection was lower with valganciclovir prophylaxis than with preemptive therapy (13%, 9/70 versus 23%, 16/70), but the difference was not statistically significant. Subclinical rejection at 3 months was lower in the prophylaxis group (13% versus 29%, P = 0.027). Both regimens prevented CMV disease (in 4% of patients in both groups). Compared with prophylaxis, preemptive therapy resulted in significantly higher rates of CMV DNAemia (44% versus 75%, P < 0.001) and a higher proportion of patients experiencing episodes with higher viral load (≥2000 IU/ml), but significantly lower valganciclovir exposure and neutropenia. CONCLUSION: Among kidney transplant recipients, the use of valganciclovir prophylaxis did not result in a significantly lower incidence of acute rejection compared with the use of preemptive therapy. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Optimizing Valganciclovir Efficacy in Renal Transplantation (OVERT Study), ACTRN12613000554763 .

CHEK2p.I157T Mutation Is Associated with Increased Risk of Adult-Type Ovarian Granulosa Cell Tumors.

Pathogenic germline mutations c.1100delC and p.I157T in the CHEK2 gene have been associated with increased risk of breast, colon, kidney, prostate, and thyroid cancers; however, no associations have yet been identified between these two most common European founder mutations of the CHEK2 gene and ovarian cancers of any type. Our review of 78 female heterozygous carriers of these mutations (age > 18 years) found strikingly higher proportion of adult-type granulosa cell tumors of the ovary (AGCTs) among ovarian cancers that developed in these women (~36%) compared to women from the general population (1.3%). Based on this finding, we performed a cross-sectional study that included 93 cases previously diagnosed with granulosa cell tumors, refined and validated their AGCT diagnosis through an IHC study, determined their status for the two CHEK2 mutations, and compared the prevalence of these mutations in the AGCT cases and reference populations. The prevalence ratios for the p.I157T mutation in the AGCT group relative to the global (PR = 26.52; CI95: 12.55−56.03) and European non-Finnish populations (PR = 24.55; CI95: 11.60−51.97) support an association between the CHEK2p.I157T mutation and AGCTs. These rare gynecologic tumors have not been previously associated with known risk factors and genetic predispositions. Furthermore, our results support the importance of the determination of the FOXL2p.C134W somatic mutation for accurate diagnosis of AGCTs and suggest a combination of IHC markers that can serve as a surrogate diagnostic marker to infer the mutational status of this FOXL2 allele.

SDHC Methylation Pattern in Patients With Carney Triad.

Carney triad is a multitumor syndrome affecting almost exclusively young women in a nonfamilial setting, which manifests by multifocal gastric gastrointestinal stromal tumors, paragangliomas, and pulmonary chondroma. The Carney triad-associated tumors are characterized by a deficiency of the mitochondrial succinate dehydrogenase enzymatic complex. Recently, it has been observed that the deficiency results from epigenetic silencing of the SDHC gene by its promoter hypermethylation. To elucidate anatomic distribution of SDHC promoter methylation in Carney triad patients and thus to shed some light on the possible natural development of this epigenetic change, both neoplastic and available non-neoplastic tissues of 3 patients with Carney triad were tested for hypermethylation at the SDHC promoter site. SDHC promoter hypermethylation was proven in all tumors studied. Lack of SDHC epigenetic silencing in the non-neoplastic lymphoid and duodenal tissue (ie, tissues not involved in the development of Carney triad-associated tumors) together with the finding of SDHC promoter hypermethylation in the non-neoplastic gastric wall favors the hypothesis of postzygotic somatic mosaicism as the biological background of Carney triad; it also offers an explanation of the multifocality of gastrointestinal stromal tumors of the stomach occurring in this scenario as well. However, the precise mechanism responsible for the peculiar organ-specific distribution of Carney triad-associated tumors is still unknown.

Morphological features useful in the differential diagnosis between undifferentiated carcinoma and gastrointestinal stromal tumor.

Undifferentiated (sarcomatoid) carcinomas may closely mimic gastrointestinal stromal tumors (GISTs) due to possible histological and immunohistochemical overlap between these two entities. To avoid unnecessary employment of a wide spectrum of immunohistochemical stainings and molecular genetics and thus decrease costs, finding simple morphological features to target further investigation of such neoplasms of the gastrointestinal tract would be helpful. Five cases classified as undifferentiated (sarcomatoid) carcinomas with a definite proof of the diagnosis, i. e. the presence of a differentiated carcinomatous component, were retrieved from archives of several institutions. For comparison, 84 cases of GIST mutated in KIT or PDGFRA genes served as the control group. Hematoxylin and eosin stained slides were evaluated for the presence of patterns which might discriminate between sarcomatoid carcinoma and GIST. Lymphatic invasion and entrapment of fat tissue strongly favor the diagnosis of undifferentiated carcinoma, as it was found in all or almost all cases of undifferentiated carcinoma, but in no GIST. Alternation of low- and high- grade areas, formation of angiosarcomatous-like spaces, and the presence of yolk sac-like areas were also detected in all cases of undifferentiated carcinoma, but only in 1.2%, 2.4% and 7.2% of the GISTs, respectively. Furthermore, DOG1 was negative in all cases of undifferentiated carcinoma. According to this study, the presence of the histological findings listed above should prompt extensive tumor sampling in order to find a differentiated carcinomatous component. However, due to the small number of cases of undifferentiated carcinoma available for the study, a larger multi-institutional study is warranted.

The Predictive Role of Primary Tumour Sidedness in Metastatic Colorectal Cancer Treated With Targeted Agents.

BACKGROUND/AIM: The aim of our study was to assess the predictive role of primary tumour sidedness (PTS) in patients with metastatic colorectal cancer (mCRC) harbouring wild-type RAS and treated with targeted agents. PATIENTS AND METHODS: The cohort included 178 patients treated with first-line chemotherapy plus cetuximab, panitumumab or bevacizumab. RESULTS: We observed longer progression-free survival (PFS) and overall survival (OS) in patients with left-sided (L-CRC) compared to right-sided tumours (R-CRC) treated with anti-EGFR mAbs (p=0.0033 and p=0.0037), while there was no difference in patients treated with bevacizumab (p=0.076 and p=0.56). Finally, we observed longer PFS and OS in patients with L-CRC treated with anti-EGFR mAbs and those with R-CRC treated with bevacizumab compared to the reverse combination (p=0.0002 and p=0.011). CONCLUSION: PTS is a predictive factor for anti-EGFR mAbs, not for bevacizumab. Superior survival was observed when anti-EGFR mAbs were used for L-CRC and bevacizumab for R-CRC.

The Association of Baseline Serum Tumour Markers with Outcome of Patients with Metastatic Colorectal Cancer Treated with Anti-EGFR Monoclonal Antibodies in the First Line.

The measurement of serum tumour markers is a simple and non-invasive method for assessing the response to systemic therapies in metastatic colorectal cancer (mCRC) and estimation of prognosis. The aim of our retrospective study was to evaluate the association of baseline serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), thymidine kinase (TK) and tissue polypeptide specific antigen (TPS) with outcome of patients with mCRC treated with combination of chemotherapy and monoclonal antibodies against epidermal growth factor receptor (anti-EGFR mAbs) in the first line. In our study, the cohort included 102 patients treated with therapy based on anti-EGFR mAbs between years 2011 and 2017 at Department of Oncology and Radiotherapy, Medical School and University Hospital in Pilsen, Czech Republic. Serum samples were collected within one month before the initiation of treatment. In multivariate Cox analysis that included serum tumour markers and clinical baseline parameters show that high baseline serum CA 19-9 was significantly associated with worse progression-free survival (HR=1.871, p=0.0330) and also overall survival (HR=3.903, p=0.0006). We have not demonstrated association of baseline levels of CEA, TK and TPS with patients' outcome. CA 19-9 is commonly used serum tumour marker which is simple and readily available and its candidate prognostic importance in the setting of anti-EGFR therapy deserves to be studied in prospective trials.

Solid pseudopapillary neoplasm (SPN) of the testis: Comprehensive mutational analysis of 6 testicular and 8 pancreatic SPNs.

BACKGROUND: Recently, we came with the theory of a possible relationship between a group of testicular and pancreatic tumors. We used one case of a pancreatic analogue solid pseudopapillary neoplasm of the testis composed partially of areas reminiscent of solid pseudopapillary neoplasm (SPN) of the pancreas and partially of structures identical to primary signet ring stromal tumor of the testis (PSRSTT) as a connecting link between these two entities. After demonstrating that PSRSTT and pancreatic analogue SPN of the testis share the same immunoprofile and genetic features characteristic for pancreatic SPN, we came to the conclusion that pancreatic analogue SPN of the testis and PSRSTT represent a morphological spectrum of a single entity and that both are related to the pancreatic SPN. DESIGN: The aim of this study is to present a series of 6 cases of testicular tumors, which lacked the signet ring cell component and were thus morphologically very similar to the SPN of the pancreas. The goal of this study is to compare the genetic background of these testicular tumors that are obviously related to the PSRSTT/pancreatic analogue SPN of the testis with the series of 8 pancreatic SPN. RESULTS: The mutational analysis revealed an oncogenic somatic mutation in the exon 3 of the CTNNB1 (ß-catenin) gene in all analyzable (5/6) testicular and all pancreatic (8/8) tumors. The immunoprofile (positivity with ß-catenin, CD10, vimentin, NSE, CD56, and negativity with inhibin, calretinin, chromogranin) was identical in all testicular and pancreatic tumors. CONCLUSION: This study expanded the morphological spectrum of the PSRSTT/pancreatic analogue SPN of the testis by adding 6 cases without the signet ring cell component. Considering the obvious analogy of PSRSTT/pancreatic analogue SPN of the testis/SPN of the testis and their relationship to the pancreatic SPN we propose the collective term "solid pseudopapillary neoplasm of the testis" for these tumors. The mutational profile of the SPN of the testis and pancreas was the same in both groups of tumors which we consider as a final proof that SPN of the testis is identical to the SPN of the pancreas.

Primary signet ring stromal tumor of the testis: a study of 13 cases indicating their phenotypic and genotypic analogy to pancreatic solid pseudopapillary neoplasm.

Primary signet ring stromal tumor of the testis (PSRSTT) is an extremely rare tumor described only twice in the literature. Pancreatic-analogue solid pseudopapillary neoplasm (SPN) of the testis is a recently reported entity with morphological overlap with PSRSTT. We reviewed our files to find all cases of PSRSTT to better characterize this entity. We studied 13 cases of PSRSTTs using histological, immunohistochemical (IHC), and molecular genetic methods and compared the results with pancreatic SPN. Grossly, the size of PSRSTTs ranged from 0.5 to 2 cm (mean 1.1). Microscopically, PSRSTTs predominantly showed a proliferation of low-grade epithelioid cells containing characteristic cytoplasmic vacuole dislodging the nucleus (signet ring cells) separated by fibrous septa into trabeculae and nests. The immunoprofile was characterized by immunoreactivity for ß-catenin, cyclin D1 (nuclear positivity for both antibodies), CD10, vimentin, galectin-3, claudin 7, α-1-antitrypsin, CD56, and neuron-specific enolase and negativity for chromogranin, inhibin, calretinin, SF-1, NANOG, OCT3/4, and SALL4. In some cases, the IHC panel was restricted because of a limited amount of tissue. Molecular genetic analysis revealed mutations within exon 3 of the CTNNB1 encoding ß-catenin in all analyzable cases. Based on histological similarities between pancreatic SPN and PSRSTT and their identical IHC and molecular genetic features, we assume that both neoplasms share the same pathogenesis, and thus, PSRSTT can be considered as a testicular analogue of pancreatic SPN.

Nonsyndromic Intestinal Lipomas are Probably not Associated With Mutations of PDGFRA.

The purpose of this study was to test the hypothesis that intestinal lipomas occurring in patients devoid of signs of PDGFRA-mutant syndrome might represent sporadic counterparts of familial lipomatous tumors occurring in the spectrum of tumors associated with PDGFRA mutations. PDGFRA-mutant syndrome may manifest with gastrointestinal stromal tumors, Vanek tumors, fibrous tumors, and lipomatous tumors. Until now there has been no molecular genetic study of PDGFRA mutations in intestinal lipomas published in the world literature. A series of 20 intestinal lipomas were obtained from 17 patients, and mutational analysis of exons 12, 14, and 18 of the PDGFRA gene was performed. None of the 16 analyzable tumors showed mutations in PDGFRA. Thus, PDGFRA mutations probably do not play an important role in the development of sporadic lipomas of the intestines.

Cutaneous Sebaceous Lesions in a Patient With MUTYH-Associated Polyposis Mimicking Muir-Torre Syndrome.

A 76-year-old white male with a history of adenocarcinoma of the rectosigmoideum and multiple colonic polyps removed at the age of 38 and 39 years by an abdominoperitoneal amputation and total colectomy, respectively, presented with multiple whitish and yellowish papules on the face and a verrucous lesion on the trunk. The lesions were surgically removed during the next 3 years and a total of 13 lesions were investigated histologically. The diagnoses included 11 sebaceous adenomas, 1 low-grade sebaceous carcinoma, and 1 squamous cell carcinoma. In some sebaceous lesions, squamous metaplasia, intratumoral heterogeneity, mucinous changes, and peritumoral lymphocytes as sometimes seen in sebaceous lesions in Muir-Torre syndrome were noted. Mutation analysis of the peripheral blood revealed a germline mutation c.692G>A,p.(Arg231His) in exon 9 and c.1145G>A, p.(Gly382Asp) in exon 13 of the MUTYH gene. A KRAS mutation G12C (c.34G>T, p.Gly12Cys) was detected in 1 sebaceous adenoma and a NRAS mutation Q61K (c.181C>A, p.Gln61Lys) was found in 2 other sebaceous adenomas. No germline mutations in MLH1, MSH2, MSH6 and PMS2 genes, no microsatellite instability, no aberrant methylation of MLH1 promoter, and no somatic mutations in MSH2 and MSH6 were found. An identical MUTYH germline mutation was found in the patient's daughter. Despite striking clinicopathological similarities with Muir-Torre syndrome, the molecular biologic testing confirmed the final diagnosis of MUTYH-associated polyposis.

Pancreatic analogue solid pseudopapillary neoplasm arising in the paratesticular location. The first case report.

We describe the first pancreatic analogue of solid pseudopapillary neoplasm arising in paratesticular location. It was a tumor arising in 32-year-old man adhering closely to the testis. The tumor had several morphologic components. The greatest was represented by signet ring cells which gradually changed into solid, non-signet ring cell areas, often being mixed together. It also formed distinct trabeculae and pseudopapillae frequently adhering to cystic areas of the tumor. Immunohistochemically, the tumor had an identical profile to its pancreatic counterpart. The tumor cells reacted diffusely with S100 protein, ß-catenin, cyclin D1, Fli-1, vimentin, CD10, galectin-3, and neuron-specific enolase and focally with synaptophysin. CD56 and E-cadherin reacted only in those parts of the tumor, which formed pseudopapillae. Cytokeratin antibody AE1-AE3 was strongly positive in the areas of trabecular formation of the tumor. The mutational analysis of exon 3 of the CTNNB1 gene confirmed mutation in this exon.

G12V and G12A KRAS mutations are associated with poor outcome in patients with metastatic colorectal cancer treated with bevacizumab.

The v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are found in 35-45 % of colorectal cancer (CRC) cases. Although the association between the RAS signaling and angiogenesis is well known, the negative predictive value of KRAS mutation has not been established in patients treated with bevacizumab. The aim of this study was to evaluate the association between specific KRAS mutation types and outcome of patients with metastatic CRC treated with bevacizumab. The study included 404 patients with metastatic CRC (mCRC) treated with bevacizumab. Clinical data obtained from the clinical registry CORECT were retrospectively analyzed. The shortest survival was observed in patients with tumors harboring G12V or G12A KRAS mutation (G12V/A). The median progression-free survival (PFS) and overall survival (OS) for patients with tumors harboring G12V/A KRAS mutation was 6.6 and 16.8 compared to 11.6 and 26.3 months for patients with tumors harboring other KRAS mutation type (p < 0.001 and p < 0.001), while the survival of patients harboring other KRAS mutation types was comparable to those with tumors harboring wild-type KRAS gene. In the Cox multivariable analysis, KRAS G12V/A mutation type remains a significant factor predicting both PFS (HR = 2.18, p < 0.001) and OS (HR = 2.58, p < 0.001). In conclusion, the results of the present study indicate that there is a significant difference in biological behavior between tumors harboring G12V/A and other KRAS mutations. Moreover, comparison of the survival of patients with tumors harboring G12V/A KRAS mutations with those harboring wild-type KRAS gene revealed that G12V/A KRAS mutations are prognostic biomarker for inferior PFS and OS in patients with mCRC treated with bevacizumab in univariate as well as multivariable analyses.

Comparison of the prevalence of KRAS-LCS6 polymorphism (rs61764370) within different tumour types (colorectal, breast, non-small cell lung cancer and brain tumours). A study of the Czech population.

AIMS: A germline SNP (rs61764370) is located in a let-7 complementary site (LCS6) in the 3'UTR of KRAS oncogene, and it was found to alter the binding capability of the mature let-7 microRNA to the KRAS mRNA. The aim of the study was to evaluate the frequency of the KRAS-LCS6 variant allele in different cancer types that included patients with colorectal cancer (CRC), breast cancer (BC), non-small cell lung cancer (NSCLC) and brain tumour patient subgroups from the Czech Republic. The occurrence of this genetic variant was correlated with the presence of selected somatic mutations representing predictive biomarkers in the respective tumours. METHODS: DNA of tumour tissues was isolated from 428 colorectal cancer samples, 311 non-small cell lung cancer samples, 195 breast cancer samples and 151 samples with brain tumour. Analysis of SNP (rs61764370) was performed by the PCR+RFLP method and direct sequencing. KRAS, BRAF and EGFR mutation status was assessed using real-time PCR. The status of the HER2 gene was assessed using the FISH method. RESULTS: The KRAS-LCS6 TG genotype has been detected in 16.4% (32/195) of breast cancer cases (in HER2 positive breast cancer 3.3%, in HER2 negative breast cancer 20.1%), in 12.4% (53/428) of CRC cases (KRAS/BRAF wild type CRC in 10.6%, KRAS mutant CRC in 10.1%, BRAF V600E mutant CRC in 18.5%), in 13.2% (41/311) of NSCLC samples, (EGFR mutant NSCLC patients in 8%, EGFR wild type NSCLC in 12.9%), and 17.9% (27/151) of brain tumour cases. The KRAS-LCS6 TG genotype was not significantly different across the studied tumours. In our study, the GG genotype has not been found among the cancer samples. CONCLUSIONS: Based on the findings, it is concluded that the occurrence of the KRAS-LCS6 TG genotype was statistically significantly different in association with status of the HER2 gene in breast cancer. Furthermore, significant association between the mutation status of analysed somatic variants in genes of the EGFR signalling pathway (KRAS, BRAF, EGFR) and the KRAS-LCS6 genotype in colorectal cancer and NSCLC has not been established.

Large germline deletions of the CYLD gene in patients with Brooke-Spiegler syndrome and multiple familial trichoepithelioma.

Brooke-Spiegler syndrome (BSS) and its phenotypic variants, multiple familial trichoepithelioma (MFT) and familial cylindromatosis, are rare autosomal dominant hereditary diseases. They are characterized by the presence of multiple adnexal tumors, especially cylindromas, spiradenomas, spiradenocylindromas, and trichoepitheliomas. Implicated in the pathogenesis of the disease is the gene CYLD, which is localized on the long arm of chromosome 16. This gene encodes an evolutionarily conserved protein belonging to the deubiquitinating enzymes family, which plays a key role in many signaling pathways, especially in NF-κB, JNK, and Wnt. Less than 90 germline mutations of CYLD have been identified in patients with BSS/MFT. These mutations are mostly small alterations in the coding sequence and at exon-intron junction sites. One patient with an intronic mutation and another with a large CYLD deletion have also been recorded. In this study, the authors have analyzed a cohort of 14 patients with BSS/MFT from 13 families for large genome rearrangements by array comparative genome hybridization followed by confirmatory sequencing. We identified 2 large deletions, namely c.-34111_*297858del378779 and c.914-6398_1769del13642ins20 in patients with MFT and BSS, respectively. All other analyzable patients did not reveal any copy number alteration. It is concluded that the large rearrangements are relatively rare in patients without a germline CYLD mutation demonstrable by conventional sequencing. The pathogenetic mechanisms in patients with BSS/MFT lacking germline sequence alterations or large rearrangements in the CYLD gene remain to be clarified.

Succinate dehydrogenase (SDH)-deficient renal carcinoma: a morphologically distinct entity: a clinicopathologic series of 36 tumors from 27 patients.

Succinate dehydrogenase (SDH)-deficient renal carcinoma has been accepted as a provisional entity in the 2013 International Society of Urological Pathology Vancouver Classification. To further define its morphologic and clinical features, we studied a multi-institutional cohort of 36 SDH-deficient renal carcinomas from 27 patients, including 21 previously unreported cases. We estimate that 0.05% to 0.2% of all renal carcinomas are SDH deficient. Mean patient age at presentation was 37 years (range, 14 to 76 y), with a slight male predominance (M:F=1.7:1). Bilateral tumors were observed in 26% of patients. Thirty-four (94%) tumors demonstrated the previously reported morphology at least focally, which included: solid or focally cystic growth, uniform cytology with eosinophilic flocculent cytoplasm, intracytoplasmic vacuolations and inclusions, and round to oval low-grade nuclei. All 17 patients who underwent genetic testing for mutation in the SDH subunits demonstrated germline mutations (16 in SDHB and 1 in SDHC). Nine of 27 (33%) patients developed metastatic disease, 2 of them after prolonged follow-up (5.5 and 30 y). Seven of 10 patients (70%) with high-grade nuclei metastasized as did all 4 patients with coagulative necrosis. Two of 17 (12%) patients with low-grade nuclei metastasized, and both had unbiopsied contralateral tumors, which may have been the origin of the metastatic disease. In conclusion, SDH-deficient renal carcinoma is a rare and unique type of renal carcinoma, exhibiting stereotypical morphologic features in the great majority of cases and showing a strong relationship with SDH germline mutation. Although this tumor may undergo dedifferentiation and metastasize, sometimes after a prolonged delay, metastatic disease is rare in the absence of high-grade nuclear atypia or coagulative necrosis.

[Gastrointestinal stromal tumor (GIST): advances in 2013]. / Gastrointestinální stromální tumor (GIST): pokroky do roku 2013.

Gastrointestinal stromal tumors (GIST) are currently regarded as a heterogenous group of tumors sharing common histological appearance, KIT immunopositivity and supposed origin from tissue progenitor cells capable of differentiation into the phenotype of Cajal interstitial cells. GISTs can be divided according to immunoexpression of the beta subunit of mitochondrial enzyme succinate dehydrogenase (SDHB) to SDHB-positive (encompassing KIT, PDGFRA and NF1 mutated GISTs), and SDHB-deficient GISTs (including Carney-Stratakis syndrome, Carney triad, sporadic pediatric GISTs, and a small subset of sporadic adult GISTs). The individual molecular subtypes differ in biological behavior and in their response to systemic targeted therapy, which is indicated in metastatic GISTs or in tumors with high risk of recurrence. Although several risk-stratification classifications have been developed, strictly defined criteria to identify patients at risk are still lacking. Pharmacogenomics have been successful in designing drugs to overcome not only the primary resistance of GISTs to the action of imatinib (e.g. GISTs with a substitution of Asp842Val in exon 18 PDGFRA or SDHB-deficient GISTs), but also the secondary resistance caused by secondary mutation of a gene encoding either the receptor tyrosine kinase or other molecules involved in the respective signalling cascade. Future directions concentrate on rational molecular targeting for systemic therapy based on complex genetic investigation of the tumor. Peripheral blood is planned to be used as a source of information for genetic events responsible for the secondary resistance of metastatic tumors.

[Sequencing - classical method]. / Sekvenování - klasická metodika.

In this article the basic methods of reading nucleotide sequences in DNA molecules are summarized. Sanger sequencing is described most thoroughly as it is the most frequent routine method currently being utilized. The article describes in detail the principle of sequence determination through the production of fragments with a known end base using chain termination synthesis of DNA and ways of separation and detection of the fragments. Some alternative methods of sequencing are mentioned in short. Basic approaches of analyzing sequence data are explained as well as different outcomes, obstacles and challenges.

Tumor-infiltrating lymphocytes and dendritic cells in human colorectal cancer: their relationship to KRAS mutational status and disease recurrence.

The prognosis of newly diagnosed colorectal cancer patients relies mostly on tumor-node metastasis classification. However, analyses of tumor-infiltrating lymphocytes and several molecular markers have also shown promising prognostic value. Mutations in the proto-oncogene KRAS, which occur early in colorectal carcinogenesis, have been demonstrated to be common in human colorectal cancer (CRC); however, their prognostic significance remains controversial. We examined the correlations between KRAS mutational status and tumor-infiltrating immune cells with respect to CRC recurrence. Mutations in KRAS were identified in 45.5% of the primary carcinomas in our cohort of patients: 65% in codon 12 and 35% in codon 13. Although codon 13 KRAS mutations were associated with disease relapse, they were present in both disease-free and relapsed patients. However, disease-free and relapsed patients differed markedly in their patterns of tumor-infiltrating immune cells. There was a trend toward decreased density of tumor-infiltrating lymphocytes (TILs) within the group of relapsed cases. In addition, relapsed patients with codon 13 mutations had markedly lower levels of tumor-infiltrating mature DC-LAMP(+) dendritic cells (DCs) and higher frequency of CD1a(+) cells compared with disease-free patients. Our data suggest that CRC patients with low levels of TILs, a high CD1a(+)/DC-LAMP(+) tumor-infiltrating DC ratio, and a KRAS mutation in codon 13 are at a high risk of disease recurrence.

Extra nuchal-type fibroma associated with elastosis, traumatic neuroma, a rare APC gene missense mutation, and a very rare MUTYH gene polymorphism: a case report and review of the literature*.

We report a case of an extra nuchal-type fibroma in a 51-year-old male suspected to have attenuated familial adenomatous polyposis (Gardner's syndrome), who presented with a longstanding buttock mass excised due to enlargement and pain. Histopathologically, lobules of haphazard, hypocellular, hyalinized collagen bundles replaced the dermis and subcutis and entrapped nerve bundles, mimicking Morton neuroma. Ramifying nerve twigs found around larger nerve fascicles showed the co-existence of traumatic neuroma. Elastic tissue stain revealed elastosis characterized by large, arborizing fibers lying between and within the hyalinized collagen bundles. Modified Masson's trichrome stain showed light blue staining of collagen bundles producing the hyalinized nodules with irregular, light red staining of collagen bundles at their periphery and within tumor collagen. Compression and/or degeneration of collagen and secondary elastosis with later entrapment by tumor collagen could explain this microscopic phenotype. By immunohistochemistry, tumor spindle cells expressed nuclear ß-catenin and cyclin D1, mostly within regions of fibrosis implicating activation of the adenomatous polyposis coli (APC)-Wnt pathway. Genetic analysis showed a missense mutation in APC gene (c.7504G>A, p.G2502S in exon 15) and a functional homozygous polymorphism in the MUTYH gene (c.36+325G>C, (IVS1+5G/C)). Nuchal-type fibroma has been associated with Gardner's syndrome and trauma. In this patient, genetic predisposition coupled with repetitive, localized trauma and collagen degeneration may have provided the stimulus for the development of extra nuchal-type fibroma.