The Ring Study: an international comparison of PD-L1 diagnostic assays and their interpretation in non-small cell lung cancer, head and neck squamous cell cancer and urothelial cancer.

PD-L1 immunohistochemistry has been approved as a diagnostic assay for immunotherapy. However, an international comparison across multiple cancers is lacking. This study aimed to assess the performance of PD-L1 diagnostic assays in non-small cell lung cancer (NSCLC), head and neck squamous cell cancer (HNSCC) and urothelial cancer (UC). The excisional specimens of NSCLC, HNSCC and UC were assayed by Ventana SP263 and scored at three sites in each country, including Australia, Brazil, Korea, Mexico, Russia and Taiwan. All slides were rotated to two other sites for interobserver scoring. The same cohort of NSCLC was assessed with Dako 22C3 pharmDx PD-L1 for comparison. The PD-L1 immunopositivity was scored according to the approved PD-L1 scoring algorithms which were the percentage of PD-L1-expressing tumour cell (TC) and tumour proportion score (TPS) by Ventana SP263 and Dako 22C3 staining, respectively. In NSCLC, the comparison demonstrated the comparability of the SP263 and 22C3 assays (cut-off of 1%, κ=0.71; 25%, κ=0.75; 50%, κ=0.81). The interobserver comparisons showed moderate to almost perfect agreement for SP263 in TC staining at 25% cut-off (NSCLC, κ=0.72 to 0.86; HNSCC, κ=0.60 to 0.82; UC, κ=0.68 to 0.91) and at 50% cut-off for NSCLC (κ=0.64 to 0.90). Regarding the immune cell (IC) scoring in UC, there was a lower correlation (concordance correlation coefficient=0.10 to 0.68) and poor to substantial agreements at the 1%, 5%, 10% and 25% cut-offs (κ= -0.04 to 0.76). The interchangeability of SP263 and 22C3 in NSCLC might be acceptable, especially at the 50% cut-off. In HNSCC, the performance of SP263 is comparable across five countries. In UC, there was low concordance of IC staining, which may affect treatment decisions. Overall, the study showed the reliability and reproducibility of SP263 in NSCLC, HNSCC and UC.

p53 Immunohistochemistry and Mutation Types Mismatching in High-Grade Serous Ovarian Cancer.

High-grade serous carcinoma (HGSCa) of the ovary is featured by TP53 gene mutation. Missense or nonsense mutation types accompany most cases of HGSCa that correlate well with immunohistochemical (IHC) staining results-an all (missense) or none (nonsense) pattern. However, some IHCs produce subclonal or mosaic patterns from which TP53 mutation types, including the wild type of the gene, cannot be clearly deduced. We analyzed a total of 236 cases of ovarian HGSCa and tumors of other histology by matching the results of p53 IHC staining and targeted next-generation sequencing (TruSight Tumor 170 panel). Ambiguous IHCs that do not belong to the conventional "all or none" groups were reviewed to distinguish the true wild type (WT) from potentially pathogenic subclonal or mosaic patterns. There were about 9% of sequencing-IHC mismatching cases, which were enriched by the p53 c-terminal encoding nuclear localization signal and oligomerization domain, in which the subcellular locations of p53 protein were affected. Indeed, mutations in the oligomerization domain of the p53 protein frequently revealed an unmatched signal or cytosolic staining (L289Ffs*57 (Ins), and R342*). We conclude that both mutation types and IHC patterns of p53 are important sources of information to provide a precise diagnosis of HGSCa.

Human Tissue Analysis of Left Atrial Adipose Tissue and Atrial Fibrillation after Cox Maze Procedure.

Cardiac adipose tissue is a well-known risk factor for the recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation, but its correlation with maze surgery remains unknown. The aim of this study was to investigate the correlation between the recurrence of AF and the adipose component of the left atrium (LA) in patients who underwent a modified Cox maze (CM) III procedure. We reviewed the pathology data of resected LA tissues from 115 patients, including the adipose tissue from CM-III procedures. The mean follow-up duration was 30.05 ± 23.96 months. The mean adipose tissue component in the AF recurrence group was 16.17% ± 14.32%, while in the non-recurrence group, it was 9.48% ± 10.79% (p = 0.021), and the cut-off value for the adipose component for AF recurrence was 10% (p = 0.010). The rates of freedom from AF recurrence at 1, 3, and 5 years were 84.8%, 68.8%, and 38.6%, respectively, in the high-adipose group (≥10%), and 96.3%, 89.7%, and 80.3%, respectively, in the low-adipose group (<10%; p = 0.002). A high adipose component (≥10%) in the LA is a significant risk factor for AF recurrence after CM-III procedures. Thus, it may be necessary to attempt to reduce the perioperative adipose portion of the cardiac tissue using a statin in a randomized study.

Optimal combination of immunohistochemical markers for subclassification of non-small cell lung carcinomas: A tissue microarray study of poorly differentiated areas.

BACKGROUND: Recently, studies have been reported on the optimal immunohistochemical markers for subclassification of non-small cell lung carcinoma (NSCLC). The main pitfall in subclassification of NSCLC is small specimen with poorly differentiated area. In this study, we added newly proposed markers (e.g., napsin A, SOX2) to conventional markers (p63, TTF-1, CK5/6, and CK7) and evaluated optimal combination for subtyping of NSCLC, primarily focusing on the poorly differentiated area. METHODS: Eighty two resected NSCLCs with poorly differentiated areas were classified based on histologic findings. After histologic review, only poorly differentiated areas were selected and tissue microarrays were constructed to simulate small biopsy conditions. A total of 36 adenocarcinomas (ADCs), 38 squamous cell carcinomas (SQCCs), and 8 large cell carcinomas were included. All specimens were stained with TTF-1, napsin A, CK7, p63, CK5/6, and SOX2. RESULTS: With respect to ADC, TTF-1 was positive in 19 of 36 cases (53%) and napsin A was in 25 of 36 (69%). Both markers were specific for ADC (100% and 98%, respectively). With TTF-1 and napsin A in combination, sensitivity increased to 75%. CK7 was sensitive (92%) but not specific marker (76%) for ADC. With respect to SQCC, p63 was positive in 35 of 38 cases (92%) and CK5/6 was in 23 (61%). Both markers were specific for SQCC (both 93%). With p63 and CK5/6 in combination, sensitivity increased slightly to 95%, but specificity was lower at 91%. SOX2 was specific (100%) but not sensitive marker (53%) for SQCC. Combinations did not substantially increase the diagnostic performance. CONCLUSION: A simple panel of napsin A, TTF-1, and p63 can be sufficient to reliably subclassify poorly differentiated areas of NSCLC.

Application of tissue microarray for atherectomized tissues from peripheral arterial disease.

It is not easy to apply tissue microarray (TMA) to atherectomized tissues from peripheral arterial disease because of their physical properties. We introduce a new TMA application technique for atherectomized tissues. Using a pre-made plastic TMA cassette and TMA punch device, we successfully made the TMA block containing 40 vertically oriented atherectomized tissue samples from 10 patients. The histogram of surface areas of tissue cores in the TMA showed a bell-shaped distribution, whereas that of conventionally embedded tissues showed wide distribution. This finding suggests that the TMA method might be a better way of vertical embedding than the conventional method. A TMA block prepared by our method enabled a simultaneous evaluation of the histopathology of vertically oriented atherectomized tissues and the correlation between them with intravascular ultrasound image. In addition, this new method might be applied to various tissues in different ways.

Glassy cell carcinoma predominantly commits to a squamous lineage and is strongly associated with high-risk type human papillomavirus infection.

SUMMARY: Glassy cell carcinoma (GCC) has been believed to have originated from reserve or uncommitted cells as a poorly differentiated adenosquamous carcinoma. This study includes immunoprofiles of p63, cytokeratin 17 (CK17), and CD44 to clarify which lineage of GCC is committed to human papillomavirus (HPV) detection, and to verify whether or not HPV plays a role in GCC. Nine uterine GCCs showing overwhelmingly glassy features were evaluated by an HPV genotyping chip and by immunohistochemistry for E-cadherin, CD44, p63, CEA, erb-B2, cytokeratin 17, and p16. An HPV genotyping DNA chip array with multiple oligonucleotide probes of L1 sequences from 26 types of HPV was introduced. GCCs were variably stained, except for CD44 which was stained unanimously. A lack of E-cadherin was found in 4 cases, frequent expression of p63 in 6/9 (66.7%), mucin stain or CEA in 5/9 (55.6%), and coexpression of p63 in 4. HPV prevalence in GCC was found in 6/9 cases (66.7%). HPV-18 and HPV-32 were the most common types detected. The remaining cancers were infected by HPV-31, HPV-35, HPV-39, and HPV-68. Multiple infections were found in 2 out of 6 cases. GCC could not be precisely categorized, but was committed to squamous lineages and was strongly associated with high-risk type HPV infection.