Modern Pathology最新文献

Periductal stromal tumors of the breast (PDST) are rare biphasic neoplasms with morphologic similarities to phyllodes tumors (PT). The histologic spectrum of PDST is broad but has not been well-characterized, and their genetic underpinnings remain unknown. We profiled PDST by targeted next-generation sequencing (NGS) in correlation with their histomorphology, immunophenotype, and clinical characteristics (n=15). All patients were female, including 2 with Li-Fraumeni Syndrome, with a mean age of 48 years. Forty-two percent had synchronous or metachronous PT and/or fibroadenoma. Most PDST expressed CD34 (15/15), SMA (12/14), and at least focal nuclear HMGA2 (8/12) and/or beta-catenin (6/12). High-grade PDST (HGPDST, n=8) were defined by marked nuclear pleomorphism (8/8), and most had high (≥10 mitoses/10 HPF) and/or atypical mitotic activity (7/8) and pleomorphic multinucleated tumor cells (7/8). All HGPDST had p53 (88%, 7/8) and/or Rb/CDKN2A (75%, 6/8) alterations by NGS or immunohistochemistry. p53 aberrations correlated with the presence of pleomorphic multinucleated tumor cells. Both Li-Fraumeni Syndrome patients had HGPDST with loss-of-heterozygosity of the germline TP53 variant. Other altered genes in HGPDST included EGFR (25%, 2/8), NF1 (25%, 2/8), TERT promoter, PIK3CA, CDKN2A/B, LZTR1, KMT2B, and ARID2 (1 case each). Low-grade PDST (LGPDST), which lacked marked pleomorphism, high mitotic activity, or atypical mitoses (n=7), had simpler genomes than HGPDST and lacked bona fide cancer gene alterations, with TERT promoter mutation in 1 case. Copy number alterations in PDST overlapped with those reported in PT, including 13q loss in all HGPDST. Copy number profiling revealed shared clonality of synchronous LGPDST and PT in 1 patient. In summary, we describe herein the genetic landscape of PDST, demonstrate correlation of genetic features with high-grade versus low-grade histology, and identify TP53 among key oncogenic drivers of HGPDST, including in Li-Fraumeni Syndrome. The genetics of HGPDST overlap with borderline or malignant PT, consistent with their classification as PT variants that arise through a MED12-independent pathway.

Adenocarcinoma of the lung (LUAD) is common and highly lethal. Clinical grading of LUAD strongly predicts recurrence and survival after surgery and is determined by morphological assessment of histological growth patterns in resected tumours. In particular, the two archetypally lethal morphologies, solid and micropapillary growth patterns, are highly distinct from each other but little is known about their defining molecular features, or how their appearances are related to their biology and mechanisms of lethality. Pure epithelial growth patterns and subregions were identified within 7 distinct LUAD growth patterns across 51 resected tumours and characterised using NanoString GeoMx Digital Spatial Profiler (DSP) in 160 epithelially pure regions of interest. Results were validated in 27 cases at the protein level using Akoya PhenoImager multiplex immunofluorescence, in 432 cases at the RNA level with Tempo-Seq and in 30 cases with independent GeoMx DSP. Analyses of gene expression reveal fundamental divergent evolutionary trajectories leading to solid and micropapillary growth. Additionally, we identify recurrent localised intratumoral plasticity in both growth patterns. These states can explain the origins of growth pattern and their mechanisms of virulence. Our work highlights dramatic divergence in gene expression programmes between highly lethal modes of LUAD tumour growth. We go on to show how microscopically localised hypoxia in the primary tumour helps to establish and maintain cellular survival strategies and tumour architecture suggesting morphology-specific mechanisms of LUAD tumour metastasis, and suggesting new therapeutic vulnerabilities.

Follicular lymphoma (FL) patients have variable outcomes, underscoring the need for biomarkers for improved risk stratification. Current FL grading systems, based on subjective centroblast counts, suffer from poor reproducibility, despite evidence linking grade 3 FL to worse prognosis. We aimed to identify objective biomarkers for centroblasts and centrocytes to improve FL prognostication. We reanalyzed publicly available spatial and single-cell transcriptomic data from normal germinal centers (GCs) and FL samples. Reanalysis revealed distinct gene expression profiles: AICDA (AID) and CXCR4 highly expressed in GC dark zone cells (centroblasts), and CD40 and TFRC (CD71) in light zone cells (centrocytes). Single-cell RNA sequencing of FL samples further showed AID and CXCR4 overexpression in malignant Grade 3A cells and CD40 and CD71 in grade 1-2 cells. We validated these findings using immunohistochemistry (IHC) (single and multiplex) on tonsils and 59 FL specimens (42 Grade 1-2, 17 Grade 3). Grade 3 FL showed significantly higher expression of AID, CD71, and Ki67 compared to grade 1-2; with CXCR4 approaching significance. Receiver operating characteristic (ROC) curve analysis identified optimal cut-offs for AID (1.54%), CXCR4 (21.9%), Ki67 (21.6%), and CD71 (7.57%) to distinguish grade 3 from grade 1-2 FL, with AID showing the best discriminatory ability. Crucially, AID expression evaluation showed reproducibility across two different digital algorithms and two independent visual observers. Furthermore, we observed a trend toward shorter disease-specific survival (DSS) in patients with both FL grade 3 and high AID expression. This prognostic observation held true regardless of whether AID overexpression was assessed via digital evaluation (cut-off: 1.54%) or visual estimation (cut-off: 2%). In conclusion, AID, CXCR4, CD71, and Ki67 are promising biomarkers for objectively identifying FL grade 3, potentially enhancing the reproducibility of grading and serving as independent prognostic tools. Further clinical validation in uniformly treated FL cohorts is warranted.

The diagnosis of oral epithelial dysplasia has a high degree of inter- and intra-observer variability. It is especially challenging to distinguish dysplasia from reactive squamous mucosa in the context of concurrent candidiasis. The accurate and timely diagnosis of dysplasia is imperative for patient outcomes, as progression to invasive squamous cell carcinoma will result in significant morbidity and mortality. The current management for patients with candidiasis is to treat with antifungals and re-biopsy if refractory. The treatment may be trialed for a few months, thus delaying appropriate treatment if underlying dysplasia is not identified. In this study, we collected cases of oral candidiasis with atypia and characterized them into molecularly defined groups using targeted next generation sequencing, fluorescence in situ hybridization, and p53, p16, and MTAP immunohistochemistry. We identify distinct molecular signature using immunohistochemical markers to capture oral dysplasia with concurrent candidiasis. We also postulate that p53 wild-type, p16 abnormal oral epithelial dysplasia cases are precursor lesions to p53 wild-type, p16 abnormal squamous cell carcinoma. In addition, we identify p53 wild-type, p16 wild-type oral epithelial dysplasia with verruciform and acanthotic features with HRAS or PIK3CA alterations as precursors to verrucous carcinoma. The proposed pattern-based p16 and p53 algorithm in our study will not only more accurately diagnose dysplasia in the context of oral candidiasis, but may also provide prognostically significant information to guide clinical management of oral dysplastic lesions.

Poor prognosis has been reported for patients with SMAD4 deficient (dSMAD4) colorectal adenocarcinomas (CRCs). However, it remains unclear whether unique tumor morphologies or other advanced disease signatures might stratify those patients. To reappraise this possibility across a homogenous cohort of CRC patients with advanced-stage disease, we leveraged next generation sequencing (NGS) data to identify fifty dSMAD4 CRCs at our institution. An equal number NGS-verified SMAD4 proficient (pSMAD4) CRCs were identified in parallel, yielding a control group with similar demographics, clinicopathologic parameters, and background genetic drivers as the dSMAD4 test group. Although both groups progressed to AJCC stage IV metastatic disease at high rates (dSMAD4: 90%, pSMAD4: 86%), dSMAD4 CRC specimens were enriched with overtly high-grade (HG) mucinous and non-mucinous histomorphologies (dSMAD4: 44%; pSMAD4: 12%; p=0.0007). The HG subset drove poor prognosis in dSMAD4 CRCs, as those patients developed widely metastatic disease (p=0.0048) with short overall and progression-free survival (p≤0.0001). Metastasis of unknown primary was not uncommon for HG dSMAD4 CRCs, posing diagnostic challenges in those instances. However, all dSMAD4 CRCs retained positive immunolabeling for either CDX2 or SATB2 irrespective of grade, thereby aiding diagnosis and distinguishing the HG subset from other HG CRCs that lose these biomarkers. Our reappraisal identifies an underappreciated class of HG dSMAD4 CRCs that progresses rapidly to widely metastatic disease with a dismal prognosis. Although HG morphologies may mask CRC origins, immunohistochemistry retains diagnostic utility for dSMAD4 CRCs.