RET mutation and increased angiogenesis in medullary thyroid carcinomas

Advanced medullary thyroid cancers (MTCs) are now being treated with drugs that inhibit receptor tyrosine kinases, many of which involved in angiogenesis. Response rates vary widely, and toxic effects are common, so treatment should be reserved for MTCs likely to be responsive to these drugs. RET mutations are common in MTCs, but it is unclear how they influence the microvascularization of these tumors. We examined 45 MTCs with germ-line or somatic RET mutations (RETmut group) and 34 with wild-type RET (RETwt). Taqman Low-Density Arrays were used to assess proangiogenic gene expression. Immunohistochemistry was used to assess intratumoral, peritumoral and nontumoral expression levels of VEGFR1, R2, R3, PDGFRa, PDGFB and NOTCH3. We also assessed microvessel density (MVD) and lymphatic vessel density (LVD) based on CD31-positive and podoplanin-positive vessel counts, respectively, and vascular pericyte density based on staining for a-smooth muscle actin (a-SMA), a pericyte marker. Compared with RETwt tumors, RETmut tumors exhibited upregulated expression of proangiogenic genes (mRNA and protein), especially VEGFR1, PDGFB and NOTCH3. MVDs and LVDs were similar in the two groups. However, microvessels in RETmut tumors were more likely to be a-SMA positive, indicating enhanced coverage by pericytes, which play key roles in vessel sprouting, maturation and stabilization. These data suggest that angiogenesis in RETmut MTCs may be more intense and complete than that found in RETwt tumors, a feature that might increase their susceptibility to antiangiogenic therapy. Given their increased vascular pericyte density, RETmut MTCs might also benefit from combined or preliminary treatment with PDGF inhibitors

Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity

The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)

Cytological features of "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" and their correlation with tumor histology

Among thyroid papillary carcinomas (PTCs), the follicular variant is the most common and includes encapsulated forms (EFVPTCs). Noninvasive EFVPTCs have very low risk of recurrence or other adverse events and have been recently proposed to be designated as noninvasive follicular thyroid neoplasm with papillary-like nuclear features or NIFTP, thus eliminating the term carcinoma. This proposal is expected to significantly impact the risk of malignancy associated with the currently used diagnostic categories of thyroid cytology. In this study, we analyzed the fine needle aspiration biopsy (FNAB) cytology features of 96 histologically proven NIFTPs and determined how the main nuclear features of NIFTP correlate between cytological and histological samples. Blind review of FNAB cytology from NIFTP nodules yielded the diagnosis of "follicular neoplasm" (Bethesda category IV) in 56% of cases, "suspicious for malignancy" (category V) in 27%, "atypia of undetermined significance/follicular lesion of undetermined significance" (category III) in 15%, and "malignant" (category VI) in 2%. We found good correlation (\u3ba = 0.62) of nuclear features between histological and cytological specimens. NIFTP nuclear features (size, irregularities of contours, and chromatin clearing) were significantly different from those of benign nodules but not from those of invasive EFVPTC. Our data indicate that most of the NIFTP nodules yield an indeterminate cytological diagnosis in FNAB cytology and nuclear features found in cytology samples are reproducibly identified in corresponding histology samples. Because of the overlapping nuclear features with invasive EFVPTC, NIFTP cannot be reliably diagnosed preoperatively but should be listed in differential diagnosis of all indeterminate categories of thyroid cytology

Should subcentimeter non-invasive encapsulated, follicular variant of papillary thyroid carcinoma be included in the noninvasive follicular thyroid neoplasm with papillary-like nuclear features category?

Objective: In 2016, non-invasive, well-circumscribed and encapsulated, follicular variant of papillary thyroid carcinoma (NI-EFV PTC) was reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in order to reduce overtreatment of this indolent tumor. However, the study cohort did not include subcentimeter tumors, i.e., papillary thyroid microcarcinoma (mPTC) with NI-EFV morphology, and such lesions are still regarded and staged by most pathologists as microcarcinomas. It is therefore crucial to evaluate the clinical outcome of subcentimeter NI-EFVs. Methods: A total of 52 patients with unifocal mPTC, NI-EFV from five tertiary hospitals who had at least one year clinical follow-up (FU) without post-operative RAI administration were included in the study. A control group of 57 invasive mPTC follicular variant was also included. Results: The median tumor size was 0.44 cm (range 0.1â\u80\u930.9 cm). There were no distant or lymph node metastases at diagnosis in all patients. Twenty-three patients (44%) underwent lobectomy alone, while the remaining received total thyroidectomy. No recurrence was observed in the entire cohort (n = 52) including all 38 patients with at least 2 years of FU (median FU: 6.3 years). Among 25 patients with â\u89¥5 years of FU, none recurred with a median FU of 9.6 years (range 5.2â\u80\u9318.1 years). In contrast, in the control group with invasive mPTC follicular variant, there were 5 (9%) patients with nodal metastasis at presentation and 1 (2%) who displayed nodal recurrence. Conclusion: Papillary thyroid microcarcinoma, NI-EFV, when stringently selected for, lacks metastasis at presentation and follows an extremely indolent clinical course, even when treated conservatively without RAI therapy. Provided stringent inclusion criteria are met, classification of subcentimeter mPTC, NI-EFV as NIFTP should be considered in order to avoid overtreatment of these biologically indolent lesions

Outcome and molecular characteristics of non-invasive encapsulated follicular variant of papillary thyroid carcinoma with oncocytic features

Purpose: In 2016, non-invasive encapsulated follicular variant of papillary thyroid carcinoma (NI-EFVPTC) was renamed as noninvasive thyroid follicular neoplasm with papillary-like nuclear features (NIFTP). However, as the study cohort did not mention tumors with oncocytic features, such lesions are still labeled by some as FVPTC. It is therefore crucial to evaluate the outcome and molecular profile of oncocytic NI-EFVPTC. Methods: A multi-institutional clinico-pathologic review was conducted to select 61 patients having oncocytic NI-EFVPTC. A detailed molecular profile was carried out in 15 patients. Results: Oncocytic NI-EFVPTCs predominantly affected women in their 50s. There was no distant metastasis, lymph node metastases, or structural recurrence in the entire cohort. Among patients with ≥5 years of FU, all 33 individuals did not recur with a median FU of 10.2 years. Oncocytic NI-EFVPTC commonly had RAS (33%) mutations, a high frequency of mitochondrial DNA mutations (67%) and multiple chromosomal gains/losses (53%). No fusion genes were detected. Conclusions: Oncocytic NI-EFVPTC, when stringently selected for, lacks metastasis at presentation and follows an extremely indolent clinical course, even when treated conservatively with lobectomy alone without RAI therapy. These tumors share a similar mutational profile as NIFTP, FVPTC, and follicular neoplasm and are predominantly RAS-related. Like Hurthle cell neoplasms, they harbor a high frequency of mitochondrial DNA mutations, which contribute to the oncocytic cytomorphology. However, they lack the widespread chromosomal alterations observed in Hurthle cell carcinoma. Consideration should be given to include oncocytic NI-EFVPTCs as NIFTP in order to avoid overtreatment of these highly indolent tumors

BRAF V600E and risk stratification of thyroid microcarcinoma: a multicenter pathological and clinical study

Studies from single institutions have analyzed BRAF in papillary microcarcinomas, sometimes with contradictory results. Most of them have provided limited integration of histological and clinical data. To obtain a comprehensive picture of BRAF V600E-mutated microcarcinomas and to evaluate the role of BRAF testing in risk stratification we performed a retrospective multicenter analysis integrating microscopical, pathological, and clinical information. Three hundred and sixty-five samples from 300 patients treated at six medical institutions covering different geographical regions of Italy were analyzed with central review of all cases. BRAF V600E statistical analysis was conducted on 298 microcarcinomas from 264 patients after exclusion of those that did not meet the required criteria. BRAF V600E was identified in 145/298 tumors (49%) including the following subtypes: 35/37 (95%, P<0.0001) tall cell and 72/114 (64%, P<0.0001) classic; conversely 94/129 follicular variant papillary microcarcinomas (73%, P<0.0001) were BRAF wild type. BRAF V600E-mutated microcarcinomas were characterized by markedly infiltrative contours (P<0.0001) with elongated strings of neoplastic cells departing from the tumor, and by intraglandular tumor spread (P<0.0001), typically within 5 mm of the tumor border. Multivariate analysis correlated BRAF V600E with specific microscopic features (nuclear grooves, optically clear nuclei, tall cells within the tumor, and tumor fibrosis), aggressive growth pattern (infiltrative tumor border, extension into extrathyroidal tissues, and intraglandular tumor spread), higher American Thyroid Association recurrence risk group, and non-incidental tumor discovery. The following showed the strongest link to BRAF V600E: tall cell subtype, many neoplastic cells with nuclear grooves or with optically clear nuclei, infiltrative growth, intraglandular tumor spread, and a tumor discovery that was non-incidental. BRAF V600E-mutated microcarcinomas represent a distinct biological subtype. The mutation is associated with conventional clinico-pathological features considered to be adverse prognostic factors for papillary microcarcinoma, for which it could be regarded as a surrogate marker. BRAF analysis may be useful to identify tumors (BRAF wild type) that have negligible clinical risk.Modern Pathology advance online publication, 14 August 2015; doi:10.1038/modpathol.2015.92

Guide for the Design and Construction of Externally Bonded Fibre Reinforced Inorganic Matrix Systems for Strengthening Existing Structures

The FRCM (Fibre-Reinforced Cementitious Matrix/Mortar) composites are nowadays used in structural rehabilitation interventions, more and more frequently, instead of classic FRP fibre reinforced composites (Fibre Reinforced Polymer), made with long glass, carbon or aramid fibres immersed in polymeric matrices (such as epoxy resins). In international literature the first are also called TRC (Textile Reinforced Concrete), TRM (Textile Reinforced Mortars), FRM (Fabric Reinforced Mortar) or even IMG (Inorganic Matrix-Grid Composites). In the following, since the acronym FRCM has been adopted in already approved Italian ministerial documents, it is preferred to continue using the same acronym. FRCM composites are the result of coupling nets, made with the same fibres mentioned above, or with others which have appeared more recently on the building materials market, with an inorganic matrix based on lime or cement mortar. Innovative fibres include basalt, PBO (Polyparaphenylene benzobisoxazole) and steel. In particular, this last material, very common in the construction field, is proposed again for use in FRCMs, in a version with highly enhanced mechanical performance, thanks to a particular processing process. The inorganic matrix has numerous advantages over the organic FRP matrix, especially for applications to masonry structures, given its greater affinity with this type of substrate. At the moment some guidelines are available in the international field for the qualification of FRCMs and for the design of structural reinforcement interventions carried out with such materials. In this connection the US acceptance criteria (ACI 434 - Acceptance Criteria for Masonry and Concrete Strengthening Using Fiber-Reinforced Cementitious Matrix (FRCM) Composite Systems, issued by ICC Evaluation Service, 2018) and the design guidelines (RILEM TC 250-CSM &amp; ACI 549 - Guide to Design and Construction of Externally Bonded Fabric-Reinforced Cementitious Matrix (FRCM) and Steel Reinforced Grout (SRG) Systems for Repair and Strengthening Masonry Structures, pending approval) can be mentioned. In recent years, the scientific interest in the innovative applications of FRCMs for structural rehabilitation, on the one hand, and the special nature of the widely varied Italian building heritage on the other, have attracted the interest of numerous researchers operating in the fields of Structural Mechanics, Construction, Structural Rehabilitation and Seismic Engineering. It is clear that the drafting of an Italian Guideline for the design and construction of strengthening interventions with FRCMs could no longer be postponed; above all, the drafting of a wide ranging document usable for the different types present in the national building heritage, from the masonry to the concrete constructions, as well as for the many FRCM products currently present on the national market that are different in nature of the matrix and the net reinforcement. The CNR, through its Advisory Committee on Technical Recommendations for Construction, promptly felt this need and made efforts to satisfy it by setting up a Working Group in June 2016 with the task of drawing up a Guideline for the design and construction of externally bonded fibre reinforced inorganic matrix systems for strengthening existing structures. In July 2017, the CNR Advisory Committee approved a first draft of this Technical Document on a proposal from the Working Group. Subsequently, the Working Group expanded to include all interested Italian researchers already scientifically committed to the topic, and benefited from the invaluable contribution of the FRCM manufacturers. It was thus possible to draw up the present version of the Technical Document, broader than the initial draft and characterized by more advanced applications and more sophisticated approaches which are at the frontier of current international research on the topic of structural reinforcement with FRCM