Prognostic significance of a comprehensive histological evaluation of reticulin fibrosis, collagen deposition and osteosclerosis in primary myelofibrosis patients

Application Value of 68 Ga-FAPI PET/CT in the Evaluation of Myelofibrotic Diseases

PURPOSE

Fibroblast activation protein is highly expressed in neoplastic lesions and various fibrotic tissues, making it an attractive target for disease evaluation. 68 Ga-labeled fibroblast activation protein inhibitor (FAPI), a new tumor interstitial imaging agent, holds promise for evaluating myelofibrosis. Therefore, this study aimed to use 68 Ga-FAPI PET/CT for the noninvasive visualization and quantification of the extent of myelofibrosis.

PATIENTS AND METHODS

This was a prospective clinical study involving 22 patients with myelofibrosis who underwent 68 Ga-FAPI PET/CT. The uptake of 68 Ga-FAPI was measured in their respective bone marrow and spleen, and the obtained imaging findings were compared with laboratory, cytogenetic, and histopathological data.

RESULTS

68 Ga-FAPI uptake in the bone marrow was significantly and positively correlated with the myelofibrosis grade ( r > 0.8, P < 0.001). 68 Ga-FAPI PET/CT showed visually negative results in patients with grades 0-1 myelofibrosis and positive in those with grades 2-3, but the level of involvement varied. 68 Ga-FAPI PET/CT provides a noninvasive means of visualizing the extent of systemic bone marrow involvement and differentiation between the early and advanced stages of fibrosis.

CONCLUSIONS

68 Ga-FAPI PET/CT shows promise as a method for visualizing and quantifying myelofibrosis, providing suitable sites for bone marrow biopsy. The extent of 68 Ga-FAPI uptake by bone marrow increases with the progression of myelofibrosis, thus it is a simple and noninvasive measurement that can be used to evaluate the progression of myelofibrosis. Nevertheless, although 68 Ga-FAPI PET/CT has demonstrated a potential value in prognostic assessment, further confirmation is needed.

Deep learning system for true- and pseudo-invasion in colorectal polyps

Over 15 million colonoscopies were performed yearly in North America, during which biopsies were taken for pathological examination to identify abnormalities. Distinguishing between true- and pseudo-invasion in colon polyps is critical in treatment planning. Surgical resection of the colon is often the treatment option for true invasion, whereas observation is recommended for pseudo-invasion. The task of identifying true- vs pseudo-invasion, however, could be highly challenging. There is no specialized software tool for this task, and no well-annotated dataset is available. In our work, we obtained (only) 150 whole-slide images (WSIs) from the London Health Science Centre. We built three deep neural networks representing different magnifications in WSIs, mimicking the workflow of pathologists. We also built an online tool for pathologists to annotate WSIs to train our deep neural networks. Results showed that our novel system classifies tissue types with 95.3% accuracy and differentiates true- and pseudo-invasions with 83.9% accuracy. The system's efficiency is comparable to an expert pathologist. Our system can also be easily adjusted to serve as a confirmatory or screening tool. Our system (available at http://ai4path.ca ) will lead to better, faster patient care and reduced healthcare costs.

Cutaneous involvement in Ph-negative myeloproliferative neoplasms: from extramedullary hematopoiesis to myeloid metastasis with histiocytic differentiation. A systematic review of the literature

Myeloid neoplasms may metastasize to the skin, presenting a wide range of clinical-pathological features that often lead to a reduction in patients' survival. The presentation varies depending on the category of myeloid neoplasm and its prognostic significance. The literature has specifically focused on the features of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and chronic myelomonocytic leukemia (CMML). In this article, we aimed to uncover the peculiarities of clonal skin proliferations in the course of Ph-negative myeloproliferative neoplasms (MPNs). We conducted a systematic review and statistical analysis of the literature data. MPN patients mainly exhibited cutaneous extramedullary hematopoiesis, while a minority displayed cutaneous histiocytic lesions. Furthermore, these patients showed lower survival rates compared to the median survival of MPN patients, especially when calculating survival from the appearance of cutaneous lesions. Our work highlights, for the first time, the prognostic relevance and histological heterogeneity of cutaneous lesions in MPN. Moreover, it emphasizes the importance of dermatological and histological examinations when cutaneous lesions are present.

Myelofibrosis progression grading based on type I and type III collagen and fibrillin 1 expression boosted by whole slide image analysis

AIMS

The progression of primary myelofibrosis is characterised by ongoing extracellular matrix deposition graded based on 'reticulin' and 'collagen' fibrosis, as revealed by Gomori's silver impregnation. Here we studied the expression of the major extracellular matrix proteins of fibrosis in relation to diagnostic silver grading supported by image analysis.

METHODS AND RESULTS

By using automated immunohistochemistry, in this study we demonstrate that the expression of both types I and III collagens and fibrillin 1 by bone marrow stromal cells can reveal the extracellular matrix scaffolding in line with myelofibrosis progression as classified by silver grading. 'Reticulin' fibrosis indicated by type III collagen expression and 'collagen' fibrosis featured by type I collagen expression were parallel, rather than sequential, events. This is line with the proposed role of type III collagen in regulating type I collagen fibrillogenesis. The uniformly strong fibrillin 1 immune signals offered the best inter-rater agreements and the highest statistical correlations with silver grading of the three markers, which was robustly confirmed by automated whole slide digital image analysis using a machine learning-based algorithm. The progressive up-regulation of fibrillin 1 during myelofibrosis may result from a negative feedback loop as fibrillin microfibrils sequester TGF-β, the major promoter of fibrosis. This can also reduce TGF-β-induced RANKL levels, which would stimulate osteoclastogenesis and thus can support osteosclerosis in advanced myelofibrosis.

CONCLUSIONS

Through the in-situ detection of these extracellular matrix proteins, our results verify the molecular pathobiology of fibrosis during myelofibrosis progression. In particular, fibrillin 1 immunohistochemistry, with or without image analysis, can complement diagnostic silver grading at decent cell morphology.

Continuous Indexing of Fibrosis (CIF): improving the assessment and classification of MPN patients

The grading of fibrosis in myeloproliferative neoplasms (MPN) is an important component of disease classification, prognostication and monitoring. However, current fibrosis grading systems are only semi-quantitative and fail to fully capture sample heterogeneity. To improve the quantitation of reticulin fibrosis, we developed a machine learning approach using bone marrow trephine (BMT) samples (n = 107) from patients diagnosed with MPN or a reactive marrow. The resulting Continuous Indexing of Fibrosis (CIF) enhances the detection and monitoring of fibrosis within BMTs, and aids MPN subtyping. When combined with megakaryocyte feature analysis, CIF discriminates between the frequently challenging differential diagnosis of essential thrombocythemia (ET) and pre-fibrotic myelofibrosis with high predictive accuracy [area under the curve = 0.94]. CIF also shows promise in the identification of MPN patients at risk of disease progression; analysis of samples from 35 patients diagnosed with ET and enrolled in the Primary Thrombocythemia-1 trial identified features predictive of post-ET myelofibrosis (area under the curve = 0.77). In addition to these clinical applications, automated analysis of fibrosis has clear potential to further refine disease classification boundaries and inform future studies of the micro-environmental factors driving disease initiation and progression in MPN and other stem cell disorders.

Targeted sequencing of candidate gene regions for myelofibrosis in dogs

Background

Myelofibrosis often lacks an identifiable cause in dogs. In humans, most primary myelofibrosis cases develop secondary to driver mutations in JAK2, CALR, or MPL.

Objectives

To determine the prevalence of variants in JAK2, CALR, or MPL candidate regions in dogs with myelofibrosis and in healthy dogs.

Animals

Twenty‐six dogs with myelofibrosis that underwent bone marrow biopsy between 2010 and 2018 and 25 control dogs matched for age, sex, and breed.

Methods

Cross‐sectional study. Amplicon sequencing of JAK2 exons 12 and 14, CALR exon 9, and MPL exon 10 was performed on formalin‐fixed, decalcified, paraffin‐embedded bone marrow (myelofibrosis) or peripheral blood (control) DNA. Somatic variants were categorized as likely‐benign or possibly‐pathogenic based on predicted impact on protein function. Within the myelofibrosis group, hematologic variables and survival were compared by variant status (none, likely‐benign only, and ≥1 possibly‐pathogenic). The effect of age on variant count was analyzed using linear regression.

Results

Eighteen of 26 (69%) myelofibrosis cases had somatic variants, including 9 classified as possibly‐pathogenic. No somatic variants were detected in controls. Within the myelofibrosis group, hematologic variables and survival did not differ by variant status. The number of somatic variants per myelofibrosis case increased with age (estimate, 0.69; SE, 0.29; P = .03).

Conclusions and Clinical Importance

Somatic variants might initiate or perpetuate myelofibrosis in dogs. Our findings suggest the occurrence of clonal hematopoiesis in dogs, with increasing incidence with age, as observed in humans.

Bone marrow microenvironment of MPN cells

In this chapter, we will discuss the current knowledge concerning the alterations of the cellular components in the bone marrow niche in Myeloproliferative Neoplasms (MPNs), highlighting the central role of the megakaryocytes in MPN progression, and the extracellular matrix components characterizing the fibrotic bone marrow.

Progression in Ph-Chromosome-Negative Myeloproliferative Neoplasms: An Overview on Pathologic Issues and Molecular Determinants

Progression in Ph-chromosome-negative myeloproliferative neoplasms (MPN) develops with variable incidence and time sequence in essential thrombocythemia, polycythemia vera, and primary myelofibrosis. These diseases show different clinic-pathologic features and outcomes despite sharing deregulated JAK/STAT signaling due to mutations in either the Janus kinase 2 or myeloproliferative leukemia or CALReticulin genes, which are the primary drivers of the diseases, as well as defined diagnostic criteria and biomarkers in most cases. Progression is defined by the development or worsening of marrow fibrosis or the progressive increase in the marrow blast percentage. Progression is often related to additional genetic aberrations, although some can already be detected during the chronic phase. Detailed scoring systems for clinical usage that are mostly applied in patients with primary myelofibrosis have been defined, and the most recent ones include cytogenetic and molecular parameters with prognostic significance. Additional different clinic-pathologic changes have been reported that may occur during the course of the disease and that are, at present, classified as WHO-defined types of progression, although they likely represent such an event. The present review is meant to provide an updated overview on progression in Ph-chromosome-negative MPN, with a major focus on the pathologic side.

Progression in Ph-Chromosome-Negative Myeloproliferative Neoplasms: An Overview on Pathologic Issues and Molecular Determinants

Progression in Ph-chromosome-negative myeloproliferative neoplasms (MPN) develops with variable incidence and time sequence in essential thrombocythemia, polycythemia vera, and primary myelofibrosis. These diseases show different clinic-pathologic features and outcomes despite sharing deregulated JAK/STAT signaling due to mutations in either the Janus kinase 2 or myeloproliferative leukemia or CALReticulin genes, which are the primary drivers of the diseases, as well as defined diagnostic criteria and biomarkers in most cases. Progression is defined by the development or worsening of marrow fibrosis or the progressive increase in the marrow blast percentage. Progression is often related to additional genetic aberrations, although some can already be detected during the chronic phase. Detailed scoring systems for clinical usage that are mostly applied in patients with primary myelofibrosis have been defined, and the most recent ones include cytogenetic and molecular parameters with prognostic significance. Additional different clinic-pathologic changes have been reported that may occur during the course of the disease and that are, at present, classified as WHO-defined types of progression, although they likely represent such an event. The present review is meant to provide an updated overview on progression in Ph-chromosome-negative MPN, with a major focus on the pathologic side.

A case of a primary myelofibrosis with progression and related literature review of progression phase genetics

Philadelphia (BCR-ABL)-negative myeloproliferative neoplasms (MPNs) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPN can transform into an accelerated or a blast phase, which is associated with poor response to standard therapy and low overall median survival. We present an interesting case of a patient with a history of PMF and progression and summarize the current studies on genetic features of myeloproliferative neoplasms in blast phase (MPN-BP) with an emphasis on PMF. Although MPN-BP show ≥20% blasts in peripheral blood or bone marrow, it is not considered as acute myeloid leukemia (AML) according to the WHO classification. While MPNs-BP typically lack genetic mutations seen in de novo AML, they commonly harbor IDH1/2, SRSF2, ASXL1, and TP53 mutations, similar to the genetic profiles of acute myeloid leukemia with myelodysplasia-related changes (AML-MRC).

The value of bone marrow, liver, and spleen imaging in diagnosis, prognostication, and follow-up monitoring of myeloproliferative neoplasms: a systematic review

Background

Diagnostic and treatment response criteria for the JAK2/CALR/MPL mutation-related myeloproliferative neoplasms (MPNs) are largely based on bone marrow (BM) biopsy results. However, these biopsies have several limitations, such as the risk of sampling error. Also, the prognostic impact of BM abnormalities is largely unclear. Although not currently used in clinical practice, imaging techniques might offer additional information. In this review, we investigated the value of BM, liver, and spleen imaging for diagnosis, prognostication, and response monitoring of the JAK2/CALR/MPL mutation-related MPNs (i.e. essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)).

Methods

A systematic literature search was performed via PubMed, Embase and the Cochrane Library up to 2020 March 26th. Of 5505 identified records, 55 publications met the eligibility criteria (i.e. containing original data on the imaging appearance of BM, spleen, or liver in adult ET, PV, or MF patients, published in a peer-reviewed journal, written in English).

Results

Many explorative studies described imaging features, sometimes with comparisons to clinical characteristics. Studies reporting measures of diagnostic accuracy included 1) splenic transient elastography to predict BM fibrosis grade in MF, 2) dynamic contrast-enhanced MRI to discern MF patients from ET patients and healthy controls, and 3) 18-fluorodeoxyglucose PET to detect residual disease after stem cell transplantation in MF. The diagnostic accuracies of radiography and ^99mTc-colloid scintigraphy were derived from several other articles. Except for the study on 18-fluorodeoxyglucose PET, we established substantial concerns regarding risk of bias and applicability across these studies, using the QUADAS-2 tool. Three publications described a correlation between imaging results and prognosis, of which one quantified the effect.

Conclusions

Based on current data, MRI (T1-weighted/STIR, Dixon) seems especially promising for the evaluation of BM fat content - and indirectly cellularity/fibrosis - in MF, and possibly for estimating BM cellularity in ET/PV. 18-fluorodeoxyglucose and 18-fluorothymidine PET/CT might be useful for evaluating BM fibrosis, with good reported accuracy of the former for the diagnosis of residual disease. Further research on these and other techniques is warranted to determine their exact value. Future researchers should improve methodology and focus on evaluation of diagnostic accuracy and prognostic implications of results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00405-7.

Important Pathologic Considerations for Establishing the Diagnosis of Myelofibrosis

Diagnostic criteria for primary myelofibrosis as defined by the 2017 revised World Health Organization (WHO) classification system incorporate clinical and laboratory findings, including driver mutational status (JAK2, MPL, CALR. and triple negative). The WHO emphasized the role of histopathology in making an accurate diagnosis of primary myelofibrosis and successfully incorporated a fibrosis scoring system and scoring schemas for collagen fibrosis and osteosclerosis. These steps represent a significant addition to the standardization of myelofibrosis evaluation and minimize the risk for misdiagnosis. This article reviews important pathologic considerations along with highlights of potentially relevant pitfalls relevant to histopathological diagnosis of myelofibrosis.

Integrating clinical, morphological, and molecular data to assess prognosis in patients with primary myelofibrosis at diagnosis: A practical approach

Currently available prognostic scoring systems in primary myelofibrosis (PMF) do not integrate clinical, histological, and molecular data, or they also required information on "other" mutations that are available in the clinical practice only in a very limited number of laboratories. In the present multicenter study, including 401 PMF patients, an integrated International Prognostic Scoring System (I-IPSS) was developed by combining IPSS, grade of bone marrow fibrosis (GBMF), and driver mutations molecular status (MS) to define PMF prognosis at diagnosis. Four prognostic categories were identified: I-IPSS-low risk (113 patients), I-IPSS-intermediate-1 risk (56 patients), I-IPSS-intermediate-2 risk (154 patients), and I-IPSS-high risk (78 patients). Median overall survival was 26.7 years in I-IPSS-intermediate-1, 10.8 in I-IPSS-intermediate-2, and 6.4 in I-IPSS-high-risk patients (log-rank test <0.0001); instead, it was not reached in the I-IPSS-low-risk cohort because of the extremely low number of registered deaths. The addition of GBMF and MS to IPSS improved the efficacy for predicting the risk of death. Indeed, the sensitivity of I-IPSS was significantly higher (P < .05) than that of IPSS, considering both total deaths and 5- and 10-year mortality. This comprehensive approach allows clinicians to evaluate mutual interactions between IPSS, GBMF, and MS and identify high-risk patients with poor prognosis who may benefit from aggressive treatments. More importantly, this integrated score can be easily applicable worldwide as it only required information that represent the good clinical practice in the management of PMF patients.

Evaluation of mandibular calcification on 3D volume images

Objectives

Bone and soft-tissue calcifications are often coincidentally diagnosed on digital panoramic radiographs (DPRs). As the use of three-dimensional (3D) images has increased in the past decade for diagnostics in the mandibular region, we evaluated 3D volume images derived from 2D panoramic images to determine if this method is suitable for early detection of calcifications in this region.

Methods

In this study, three investigators retrospectively and independently evaluated 822 DPRs. If one or more calcifications were present, the 3D volume image from that patient was retrospectively evaluated to confirm the incidental findings. A radiographic system with a low-dose mode and a high-resolution 3D-image function was used. The investigators focussed on the most common calcifications, including tonsilloliths (TL), idiopathic osteosclerosis (IO) of the mandible, carotid artery calcifications (CAC), calcified submandibular lymph nodes (hereafter, CSL), and sialoliths of the submandibular salivary gland (SSG).

Results

One or more calcifications were identified in 415 (50.5%) DPRs. In total, 718 calcifications were detected, 30.2% of which were TL, 16.3% IO, 11.3% CAC, 8.8% CSL, and 1.7% SSG. Only 287 (39.97 %) of the calcifications were confirmed on 3D volume images; of these, 29.2% were TL, 58.5% IO, 0.2% CAC, and 1.4% SSG. No CSLs were detected.

Conclusions

Not all areas shown on the DPRs were visible in the retrospectively obtained 3D volume images. Whereas DPRs are used to diagnose calcifications such as IO, TL, SSG, CAC, and CSL, the 3D volume images were only useful for confirming the existence of IO, TL, and SSG calcifications.

Megakaryocyte Contribution to Bone Marrow Fibrosis: many Arrows in the Quiver

In Primary Myelofibrosis (PMF), megakaryocyte dysplasia/hyperplasia determines the release of inflammatory cytokines that, in turn, stimulate stromal cells and induce bone marrow fibrosis. The pathogenic mechanism and the cells responsible for progression to bone marrow fibrosis in PMF are not completely understood. This review article aims to provide an overview of the crucial role of megakaryocytes in myelofibrosis by discussing the role and the altered secretion of megakaryocyte-derived soluble factors, enzymes and extracellular matrices that are known to induce bone marrow fibrosis.

Long-term effects of ruxolitinib versus best available therapy on bone marrow fibrosis in patients with myelofibrosis

BACKGROUND

Myelofibrosis (MF) is a life-shortening complication of myeloproliferative neoplasms associated with ineffective hematopoiesis, splenomegaly, and progressive bone marrow (BM) fibrosis. The oral Janus kinase (JAK) 1/JAK2 inhibitor ruxolitinib has been shown to improve splenomegaly, symptom burden, and overall survival in patients with intermediate-2 or high-risk MF compared with placebo or best available therapy (BAT).

METHODS

The effects of ruxolitinib therapy for up to 66 months on BM morphology in 68 patients with advanced MF with variable BM fibrosis grade were compared with those in 192 matching patients treated with BAT. Available trephine biopsies underwent independent, blinded review by three hematopathologists for consensus-based adjudication of grades for reticulin fibrosis, collagen deposition, and osteosclerosis.

RESULTS

Ruxolitinib treatment versus BAT was associated with greater odds of BM fibrosis improvement or stabilization and decreased odds of BM fibrosis worsening based on changes from baseline in reticulin fibrosis grade. Generally, these changes were accompanied by a sustained higher level of individual spleen size reduction and regression of leukoerythroblastosis. Patients with more advanced baseline fibrosis showed lower spleen size response.

CONCLUSIONS

The finding that long-term ruxolitinib therapy may reverse or markedly delay BM fibrosis progression in advanced MF suggests that sustained JAK inhibition may be disease-modifying.

TRIAL REGISTRATION

INCB18424-251, ClinicalTrials.gov identifier NCT00509899 .