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Programmed death-ligand 1 (PD-L1) expression on tumor cells (TCs) by immunohistochemistry is rapidly gaining importance as a diagnostic for the selection or stratification of patients with non-small cell lung cancer (NSCLC) most likely to respond to single-agent checkpoint inhibitors. However, at least two distinct patterns of PD-L1 expression have been observed with potential biological and clinical relevance in NSCLC: expression on TC or on tumor-infiltrating immune cells (ICs). We investigated the molecular and cellular characteristics associated with PD-L1 expression in these distinct cell compartments in 4,549 cases of NSCLC. PD-L1 expression on IC was more prevalent and likely reflected IFN-γ–induced adaptive regulation accompanied by increased tumor-infiltrating lymphocytes and effector T cells. High PD-L1 expression on TC, however, reflected an epigenetic dysregulation of the PD-L1 gene and was associated with a distinct histology described by poor immune infiltration, sclerotic/desmoplastic stroma, and mesenchymal molecular features. Importantly, durable clinical responses to atezolizumab (anti–PD-L1) were observed in patients with tumors expressing high PD-L1 levels on either TC alone [40% objective response rate (ORR)] or IC alone (22% ORR). Thus, PD-L1 expression on TC or IC can independently attenuate anticancer immunity and emphasizes the functional importance of IC in regulating the antitumor T cell response.

Anaplastic thyroid carcinoma (ATC) is an aggressive malignant tumor composed of undifferentiated thyroid follicular cells. Pathological diagnosis of ATC can be challenging as the tumor may show morphological overlap with other neoplasms with anaplastic morphology. Immunohistochemical demonstration of thyroid origin facilitates the diagnosis of ATC. Previous studies using the polyclonal anti-PAX8 antibody 10336-1-AP suggested that PAX8 was the most sensitive marker, expressed in up to 80% of ATC. According to a 2018 NordiQC report, the monoclonal anti-PAX8 antibody MRQ-50 has become the most commonly used anti-PAX8 antibody worldwide. However, validation of this antibody in ATC is lacking. In this study, we recruited 182 ATC cases from seven institutions. Pathology slides were subjected to histology review. PAX8 immunohistochemistry using the MRQ-50 antibody was performed in whole tissue slides (n = 147) or tissue microarray sections (n = 35). We found PAX8 expression in 54.4% of the cases, which was significantly lower than those reported in prior studies with the polyclonal antibody. PAX8 expression was positively correlated with the presence of an epithelial pattern (63.6% vs 37.5%, p = 0.0008) and a coexisting differentiated thyroid carcinoma component (71.6% vs 44.3%, p = 0.0004), but was not associated with age, gender, specimen type, or presence of giant cell and sarcomatoid patterns. In conclusion, we demonstrated PAX8 expression using the monoclonal antibody MRQ-50 in only half of the cases in a large ATC series. Pathologists should be aware that PAX8 expression in ATC is less than those reported in early studies to avoid misdiagnosis.

The tissue diagnosis of amyloidosis and confirmation of fibril protein type, which are crucial for clinical management, have traditionally relied on Congo red (CR) staining followed by immunohistochemistry (IHC) using fibril protein specific antibodies. However, amyloid IHC is qualitative, non‐standardised, requires operator expertise, and not infrequently fails to produce definitive results. More recently, laser dissection mass spectrometry (LDMS) has been developed as an alternative method to characterise amyloid in tissue sections. We sought to compare these techniques in a real world setting. During 2017, we performed LDMS on 640 formalin‐fixed biopsies containing amyloid (CR+ve) comprising all 320 cases that could not be typed by IHC (IHC−ve) and 320 randomly selected CR+ve samples that had been typed (IHC+ve). In addition, we studied 60 biopsies from patients in whom there was a strong suspicion of amyloidosis, but in whom histology was non‐diagnostic (CR–ve). Comprehensive clinical assessments were conducted in 532 (76%) of cases. Among the 640 CR+ve samples, 602 (94%) contained ≥2 of 3 amyloid signature proteins (ASPs) on LDMS (ASP+ve) supporting the presence of amyloid. A total of 49 of the 60 CR‐ve samples were ASP–ve; 7 of 11 that were ASP+ve were glomerular. The amyloid fibril protein was identified by LDMS in 255 of 320 (80%) of the IHC–ve samples and in a total of 545 of 640 (85%) cases overall. The LDMS and IHC techniques yielded discordant results in only 7 of 320 (2%) cases. CR histology and LDMS are corroborative for diagnosis of amyloid, but LDMS is superior to IHC for confirming amyloid type.

Pathologists’ assessment of sentinel lymph nodes (SNs) for breast cancer (BC) metastases is a treatment-guiding yet labor-intensive and costly task because of the performance of immunohistochemistry (IHC) in morphologically negative cases. This non-randomized, single-center clinical trial (International Standard Randomized Controlled Trial Number:14323711) assessed the efficacy of an artificial intelligence (AI)-assisted workflow for detecting BC metastases in SNs while maintaining diagnostic safety standards. From September 2022 to May 2023, 190 SN specimens were consecutively enrolled and allocated biweekly to the intervention arm ( n  = 100) or control arm ( n  = 90). In both arms, digital whole-slide images of hematoxylin–eosin sections of SN specimens were assessed by an expert pathologist, who was assisted by the ‘Metastasis Detection’ app (Visiopharm) in the intervention arm. Our primary endpoint showed a significantly reduced adjusted relative risk of IHC use (0.680, 95% confidence interval: 0.347–0.878) for AI-assisted pathologists, with subsequent cost savings of ~3,000 €. Secondary endpoints showed significant time reductions and up to 30% improved sensitivity for AI-assisted pathologists. This trial demonstrates the safety and potential for cost and time savings of AI assistance.

Objective To investigate the efficacy and mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with radiotherapy (XRT) on glioblastoma. Methods The enhanced radiosensitization by UTMD was assessed through colony formation and cell apoptosis in Human glioblastoma cells (U87MG). Subcutaneous transplantation tumors in 24 nude mice implanted with U87MG cells were randomly assigned to 4 different treatment groups (Control, UTMD, XRT, and UTMD + XRT) based on tumor sizes (100–300 mm 3 ). Tumor growth was observed for 10 days after treatment, and then histopathology stains (HE, CD34, and γH2AX) were applied to the tumor samples. A TUNEL staining experiment was applied to detect the apoptosis rate of mice tumor samples. Meanwhile, tissue proteins were extracted from animal specimens, and the expressions of dsDNA break repair-related proteins from animal specimens were examined by the western blot. Results When the radiotherapy dose was 4 Gy, the colony formation rate of U87MG cells in the UTMD + XRT group was 32 ± 8%, lower than the XRT group (54 ± 14%, p  < 0.01). The early apoptotic rate of the UTMD + XRT group was 21.1 ± 3% at 48 h, higher than that of the XRT group (15.2 ± 4%). The tumor growth curve indicated that the tumor growth was inhibited in the UTMD + XRT group compared with other groups during 10 days of observation. In TUNEL experiment, the apoptotic cells of the UTMD + XRT group were higher than that of the XRT group ( p  < 0.05). The UTMD + XRT group had the lowest MVD value, but was not significantly different from other groups ( p  > 0.05). In addition, γH2AX increased due to the addition of UTMD to radiotherapy compared to XRT in immunohistochemistry ( p  < 0.05). Conclusions Our study clearly demonstrated the enhanced destructive effect of UTMD combined with 4 Gy radiotherapy on glioblastoma. This could be partly achieved by the increased ability of DNA damage of tumor cells.

The assessment of Ki-67 in early-stage breast cancer has become an important diagnostic tool in planning adjuvant therapy, particularly for the administration of additional chemotherapy to hormone-responsive patients. An accurate determination of the Ki-67 index is of the utmost importance; however, the reproducibility is currently unsatisfactory. In this study, we addressed the predictive/prognostic value of Ki-67 index assessed by using the most reproducible methods, which were identified in the pilot phase. Paraffin blocks obtained from patients with moderately differentiated, estrogen receptor (ER)-positive early-stage breast cancer in Switzerland, who were originally randomized to the treatment arms with and without chemotherapy in the IBCSG VIII-IX trials, were retrieved. Of these 344 randomized patients, we identified 158 patients (82 treated with and 76 treated without chemotherapy) for whom sufficient tumour tissue was available. The presence of Ki-67 was assessed visually by counting 2000 cells at the periphery (A) and estimating the number of positive cells in five different peripheral regions (C), which was determined to be the most reproducible method identified the pilot phase. The prognostic and predictive value was assessed by calculating the breast cancer-free interval (BCFI) and overall survival (OS) rate. Ki-67 was considered a numerical and categorical variable when different cut-off values were used (10%, 14%, 20% and 30%). An mRNA-based subtyping by using the MammaTyper kit with the application of a 20% Ki-67 immunohistochemistry (IHC) cut-off equivalent was also performed. 158 of 344 randomized patients could be included in the Ki-67 analysis. The mean Ki-67 values obtained by using the two methods differed (A: 21.32% and C: 16.07%). Ki-67 assessed by using method A with a cut-off of 10% was a predictive marker for OS, as the hazard ratio (>10% vs. <=10%) in patients with chemotherapy was 0.48 with a 95% confidence interval of [0.19–1.19]. Further, the HR of patients treated without chemotherapy was 3.72 with a 95% confidence interval of [1.16–11.96] (p interaction =0.007). Higher Ki-67 index was not associated with outcome and using the 10% Ki-67 cut-off there was an opposite association for patients with and without chemotherapy. Ki-67 assessments with IHC significantly correlated with MammaTyper results (p=0.002). The exact counting method (A) performed via a light-microscope revealed the predictive value of Ki-67 assessment with a 10% cut-off value. Further analyses employing image analyses and/or mRNA-based-assessments in larger populations are warranted.

Mucin and mucin-like material are features of mucinous tubular and spindle renal cell carcinoma (MTS RCC) but are rarely seen in papillary renal cell carcinoma (PRCC). We reviewed 1311 PRCC and identified 7 tumors containing extracellular and/or intracellular mucinous/mucin-like material (labeled as PRCCM). We analyzed these using morphological, histochemical, immunohistochemical, and molecular genetic methods (arrayCGH, FISH). Clinical data were available for six of the seven patients (five males and one female, age range 61–78 years). Follow-up was available for four patients (2–4 years); one patient died of widespread metastases. Tumor size ranged from 3 to 5 cm (mean 3.8). Of all cases, histological architecture showed a predominantly papillary pattern. Mucin or mucin-like was extracellular in one, intracellular in three, and both intra/extracellular in three cases. All tumors were positive for AMACR, vimentin, and OSCAR, while CK7 was positive in four. Mucicarmine stain was positive in all cases, PAS in six and Alcian blue in three cases. Five tumors were positive for MUC 1, but none were positive for MUC 2, MUC 4, or MUC 6. In only four cases, genetic analysis could be performed. Gain of chromosomes 7 and 17 was found in two cases; gain of 17 only was found in one case. Loss of heterozygosity of 3p was found in one case together with polysomy of chromosomes 7 and 17. No abnormalities of VHL , fumarate dehydrogenase , and TFE3 genes were detected. We conclude that PRCCM is a rare but challenging subtype of RCC that deserves to be further studied. In all the tumors, the mucin-like material was found in those stained with mucicarmin, but other conventional and immunohistochemical stains did not reveal consistent features of a single mucin. The molecular-genetic profile of these tumors was most consistent with that of typical papillary RCC, although one case had mixed genetic features of papillary and clear RCC. PRCCM has metastatic potential, as evidenced by one case with widespread metastases. It remains to be determined whether PRCCM represents a unique tumor subtype, deserving to be distinguished from other subtypes of PRCC.

Purpose Although transcatheter arterial chemoembolization (TACE) is the most common treatment option in patients with hepatocellular carcinoma (HCC), its clinical benefits remain still controversial. Since TACE induces hypoxic necrosis in tumors, hypoxia-inducible factor 1α (HIF-1α) could critically affect biology in residual tumors after TACE treatment and subsequent prognosis. However, HIF-1α and its prognostic relevance in TACE have rarely been examined in human specimens. In the current study, we investigated the prognosis and expression of genes regulated by HIF-1α in HCC patients receiving preoperative TACE for the first time. Methods In total, 35 patients with HCC (10 patients undergoing preoperative TACE) were retrospectively studied. The prognostic significance of TACE was analyzed using Kaplan–Meier and Cox regression models. Protein levels of HIF-1α and mRNA levels of HIF-1α-associated genes were examined using immunohistochemistry (IHC) and real-time RT-PCR, respectively. Results Preoperative TACE was significantly associated with increased 2-year recurrence rate (80 vs. 36 %, P  = 0.00402) and shorter disease-free survival (DFS) time (11.9 vs. 35.7 months, P  = 0.0182). TACE was an independent prognostic factor for recurrence ( P  = 0.007) and poor DFS ( P  = 0.010) in a multivariate analysis. Immunohistochemical staining revealed in vivo activation of HIF-1α in human specimens treated with TACE. Notably, protein levels of HIF-1α were significantly increased in TACE tissues demonstrated by IHC. Transcriptional targets of HIF-1α showed mRNA expression patterns consistent with activation of HIF-1α in TACE tissues. Conclusions Our findings collectively demonstrate that preoperative TACE confers poor prognosis in HCC patients through activation of HIF-1α.

Background: E-cadherin methylation is important in gastric carcinogenesis. Reversing hypermethylation may halt the carcinogenic process. We have previously reported that Helicobacter pylori infection is associated with E-cadherin methylation in chronic gastritis patients. Aim: To examine if eradication of H pylori could reverse E-cadherin methylation. Methods: Patients with dyspepsia and positive for H pylori infection, with a mucosal biopsy showing chronic active gastritis, were randomised to receive H pylori eradication therapy (group 1, n = 41) or no treatment (group 2, n = 40), and were followed up prospectively. Gastric mucosae were taken for methylation assay at week 0 (before treatment) and week 6 (after treatment). Archived specimens of intestinal metaplasia with H pylori infection (n = 22) and without (n = 19) were retrieved for methylation analysis. Methylation was assessed using methylation specific polymerase chain reaction and sequencing. Results: Methylation at E-cadherin was detected in 46% (19/41) and 17% (7/41) of patients at weeks 0 and 6, respectively, in group 1 (p = 0.004); 78.9% (15/19) of specimens were unmethylated after eradication of H pylori. Mucosal biopsy showed chronic inactive gastritis in 35 patients, intestinal metaplasia in one, and normal mucosa in five at week 6. Methylation was detected in 47.5% (19/40) and 52.5% (21/40) of patients at weeks 0 and 6, respectively, in group 2 (P = 0.5). Gastric mucosal biopsy showed persistent chronic active gastritis in all cases. Methylation frequency did not differ in H pylori positive or negative intestinal metaplastic specimens (72.7% v 63%; p = 0.5). Conclusion:H pylori eradication therapy could reverse methylation in patients with chronic gastritis. This demonstrates an environmental effect on methylation.

Background Immunocytochemical staining with p16/Ki67 has been suggested as a promising triage biomarker in cervical cancer screening. As dual staining is a subjective method, proper training may be required to ensure safe implementation in routine laboratories and reduce risk of misclassification. We determined concordance between novice evaluators and an expert, stratified by number of slides reviewed at three reading points. Methods The study was conducted at the Department of Pathology, Randers, Denmark. Women were eligible if they were aged ≥45, had been enrolled in one of two ongoing clinical studies, and had a dual stain slide available. Dual staining was performed using the CINtec plus assay. Slides were randomly selected from three reading points at which novice evaluators had reviewed <30, ~300, and ≥500 dual stain slides respectively. Level of concordance was estimated using Cohen's Kappa, κ. Results Of 600 eligible slides, 50 slides were selected for review as recommended by the manufacturer. Median age was 68 years (range: 58‐74). Overall concordance was good (κ = 0.68, 95% confidence interval [CI]: 0.60‐0.76), with an overall agreement of 84% (95% CI: 70.9%‐92.8%). Concordance improved with increasing number of slides reviewed at a given reading point, from a moderate concordance (κ = 0.47, 95% CI: 0.05‐0.90) after reviewing <30 slides to a good concordance (κ = 0.66, 95% CI: 0.20‐0.88) and a very good concordance (κ = 0.88, 95% CI: 0.66‐1.00) after reviewing ~300 and ≥500 slides, respectively. Conclusions When interpreting dual stain slides from older women, concordance increased slightly as novice evaluators received more training and experience. Although further evaluation is warranted, these findings indicate that a significant amount of training and experience of novice evaluators may be needed to ensure accurate dual stain interpretation in this age group. Future studies should accurately describe training and experience of evaluators to enable a better comparison of concordance and diagnostic accuracy across studies. Trial registration NCT04114968 and NCT04298957. As training and experience in p16/Ki67 dual stain interpretation may affect concordance and possibly diagnostic accuracy of cervical precancer, it is important that future studies accurately describe any training and previous experience among evaluators to allow for a meaningful comparison of dual stain accuracy across studies. Furthermore, setting up proper dual stain training programs in routine screening laboratories is advisable to ensure sufficient interpretation skills among novice evaluators.