Lymph node positive pseudomyxoma peritonei

BackgroundAppendiceal mucinous neoplasms are routinely accompanied by peritoneal metastases at the time of diagnosis of the primary appendiceal tumor. In contrast, liver metastases and lymph node metastases are unusual.MethodsFrom an extensive database, patients with lymph node metastases identified at the time of primary appendiceal cancer resection were selected for special study. The clinical, treatment-related and histologic variables of this group of patients were statistically analyzed for their impact on overall survival.ResultsFrom a prospectively maintained database of 685 patients with a complete cytoreduction of a mucinous appendiceal neoplasm with peritoneal dissemination, 39 patients (5.6%) had lymph node metastases at the time of primary diagnosis. The median follow-up was 5.0 years and overall median survival was 6.0 years. Histologically, 6 of these patients (15.4%) had an appendiceal mucinous neoplasm – Intermediate type (MACA-Int). In 5 patients, the involved lymph nodes were not within the ileocolic lymph node group. The 7 patients (17.9%) who had a complete or near complete response to neoadjuvant chemotherapy prior to definite cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) showed prolonged survival (HR 4.8 (1.1, 20.5) p = 0.0323). A prior right colon resection required repeat resection in 87% of patients.ConclusionLong-term survival is unusual but occasionally seen in this group of patients. Response to neoadjuvant chemotherapy is an important determinant of a favorable outcome.     

What biologic factors predict for transformation to AML?

Transformation of myelodysplastic syndromes (MDS) into secondary acute myeloid leukemia (sAML) is defined by an arbitrary boundary of ≥20% bone marrow blasts but does not necessarily reflect a defined biological transition. The more obvious distinction lies between MDS patients that have an isolated bone marrow failure phenotype and those with excess blasts. Subtyping of MDS might be more accurately stratified into clonal cytopenias and oligoblastic leukemias, using the degree of dysplasia and blast percentage as risk features, respectively, rather than as diagnostic criteria. Transformation from MDS to sAML often involves clonal evolution or expansion of existing subclones that can be assessed by changes in variant allele frequencies of the somatic mutations that define them. There are a number of predictors for transformation that have been identified: these include mutations of genes in growth signaling pathways (NRAS, KRAS, PTPN11, FLT3), mutations in genes more commonly observed in AML (NPM1, WT1, IDH2), certain cytogenetic abnormalities (monosomy 7, complex karyotype, loss of 17p). Gene expression profiles that divide MDS into two major categories identify a progenitor gene signature subtype associated with a high risk of AML transformation. Assessing for these genetic abnormalities may better identify MDS patients at greatest risk of transformation.     

Pathogenesis of follicular lymphoma

Follicular lymphoma (FL) is presented as a germinal centre B cell lymphoma that is characterized by an indolent clinical course, but remains – paradoxically – largely incurable to date. The last years have seen significant progress in our understanding of FL lymphomagenesis, which is a multi-step process beginning in the bone marrow with the hallmark t(14;18)(q32;q21) translocation. The pathobiology of FL is complex and combines broad somatic changes at the level of both the genome and the epigenome, the latter evidenced by highly recurrent mutations in chromatin-modifying genes such as KMT2D and CREBBP. While the importance of the FL microenvironment has since long been well understood, it has become evident that somatic lesions within tumour cells re-educate normal immune and stromal cells to their advantage. Enhanced understanding of FL pathogenesis is currently leading to refined therapeutic targeting of perturbed biology, paving the way for precision medicine in this lymphoma subtype.     

New developments in the pathology and molecular biology of retroperitoneal sarcomas

Retroperitoneal sarcomas (RPS) refer to a heterogeneous group of malignancies of mesenchymal origin developing from retroperitoneal tissues and vessels. The most frequent RPS are well differentiated/dedifferentiated liposarcomas and leiomyosarcomas, but other rare histological subtypes can be observed. Over the last decade, significant advances have been made in the pathological and molecular characterization of sarcomas. These advances have led to major changes in their diagnostic management as well as in the development of new therapeutic strategies based on tumor biology and microenvironment. This review describes the current knowledge and recent findings in the pathology and molecular biology of the most frequent RPS subtypes.     

Validación de una nueva estrategia para la identificación de variantes de SARS-CoV-2 mediante secuenciación del gen espiga por Sanger

IntroductionThe emergence of multiple variants of SARS-CoV-2 during the COVID-19 pandemic is of great world concern. Until now, their analysis has mainly focused on next-generation sequencing. However, this technique is expensive and requires sophisticated equipment, long processing times, and highly qualified technical personnel with experience in bioinformatics. To contribute to the analysis of variants of interest and variants of concern, increase the diagnostic capacity, and process samples to carry out genomic surveillance, we propose a quick and easy methodology to apply, based on Sanger sequencing of 3 gene fragments that code for protein spike.MethodsFifteen positive samples for SARS-CoV-2 with a cycle threshold below 25 were sequenced by Sanger and next-generation sequencing methodologies. The data obtained were analyzed on the Nextstrain and PANGO Lineages platforms.ResultsBoth methodologies allowed the identification of the variants of interest reported by the WHO. Two samples were identified as Alpha, 3 Gamma, one Delta, 3 Mu, one Omicron, and 5 strains were close to the initial Wuhan-Hu-1 virus isolate. According to in silico analysis, key mutations can also be detected to identify and classify other variants not evaluated in the study.ConclusionThe different SARS-CoV-2 lineages of interest and concern are classified quickly, agilely, and reliably with the Sanger sequencing methodology.     

Aristolochic acids exposure was not the main cause of liver tumorigenesis in adulthood

Aristolochic acids (AAs) have long been considered as a potent carcinogen due to its nephrotoxicity. Aristolochic acid I (AAI) reacts with DNA to form covalent aristolactam (AL)–DNA adducts, leading to subsequent A to T transversion mutation, commonly referred as AA mutational signature. Previous research inferred that AAs were widely implicated in liver cancer throughout Asia. In this study, we explored whether AAs exposure was the main cause of liver cancer in the context of HBV infection in mainland China. Totally 1256 liver cancer samples were randomly retrieved from 3 medical centers and a refined bioanalytical method was used to detect AAI–DNA adducts. 5.10% of these samples could be identified as AAI positive exposure. Whole genome sequencing suggested 8.41% of 107 liver cancer patients exhibited the dominant AA mutational signature, indicating a relatively low overall AAI exposure rate. In animal models, long-term administration of AAI barely increased liver tumorigenesis in adult mice, opposite from its tumor-inducing role when subjected to infant mice. Furthermore, AAI induced dose-dependent accumulation of AA–DNA adduct in target organs in adult mice, with the most detected in kidney instead of liver. Taken together, our data indicate that AA exposure was not the major threat of liver cancer in adulthood.