Applied Immunohistochemistry & Molecular Morphology 

About: Applied Immunohistochemistry & Molecular Morphology is an academic journal published by Lippincott Williams & Wilkins. The journal publishes majorly in the area(s): Immunohistochemistry & Medicine. It has an ISSN identifier of 1533-4058. Over the lifetime, 2809 publications have been published receiving 40410 citations. The journal is also known as: AIMM & Applied immunohistochemistry and molecular morphology.

KIT (CD117): a review on expression in normal and neoplastic tissues, and mutations and their clinicopathologic correlation.

Abstract: :CD117 (KIT) is a type III receptor tyrosine kinase operating in cell signal transduction in several cell types. Normally KIT is activated (phosphorylated) by binding of its ligand, the stem cell factor. This leads to a phosphorylation cascade ultimately activating various transcription fact

Development of a Companion Diagnostic PD-L1 Immunohistochemistry Assay for Pembrolizumab Therapy in Non–Small-cell Lung Cancer

Abstract: A companion diagnostic assay was codeveloped by Dako for pembrolizumab non-small-cell lung cancer clinical trials to detect PD-L1 expression by immunohistochemistry (IHC). This automated IHC assay has been analytically verified and validated using Dako's autostainer Link 48 and 22C3 mouse anti-PD-L1 monoclonal antibody to detect the PD-L1 expression in formalin-fixed paraffin-embedded human tumor tissue specimens. The PD-L1 22C3 IHC assay was optimized for high sensitivity and specificity. Repeatability and reproducibility studies were conducted at Dako and at 3 Clinical Laboratory Improvement Amendments certified laboratories during assay development. The studies included: intersite and intrasite, interobserver and intraobserver, interinstrument, interoperator, interday, and interlot, and intraday and intrarun. All precision studies performed at Dako and external laboratories achieved >85% point-estimate agreements for all 3 agreement types (negative, positive, and overall). A clinical cutoff (tumor proportion score ≥50%) of PD-L1 expression was determined and evaluated through a phase 1 clinical trial (KEYNOTE-001) for advanced non-small-cell lung cancer patients treated with pembrolizumab. The treatment effect of pembrolizumab in the 61 subjects who had a tumor PD-L1 of tumor proportion score ≥50% was substantial, with an overall response rate of 41% (95% confidence interval, 28.6-54.3) as compared with 20.6% (95% confidence interval, 15.5-26.5) observed in the 223 subjects irrespective of PD-L1 status. PD-L1 IHC 22C3 pharmDx is a sensitive, precise, and robust companion diagnostic assay, which will facilitate safe and effective use for pembrolizumab in cancer patients.

Microsatellite Instability: A Predictive Biomarker for Cancer Immunotherapy.

Abstract: Immunotherapy has shown promising results in various types of cancers. Checkpoint inhibitor drugs developed for cancer immunotherapy have been approved by the US Food and Drug Administration (FDA) for patients with advanced melanoma, non-small cell lung cancer, renal cell carcinoma, bladder cancers, and refractory Hodgkin lymphoma. In the latest announcement, the FDA has granted accelerated approval to pembrolizumab for pediatric and adult patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient solid tumors. This is the first time the agency has approved a cancer treatment based on a common biomarker rather than organ-based approach. MSI-H, either due to inherited germline mutations of mismatch repair genes or epigenetic inactivation of these genes, is found in a subset of colorectal and noncolorectal carcinomas. It is known that MSI-H causes a build up of somatic mutations in tumor cells and leads to a spectrum of molecular and biological changes including high tumor mutational burden, increased expression of neoantigens and abundant tumor-infiltrating lymphocytes. These changes have been linked to increased sensitivity to checkpoint inhibitor drugs. In this mini review, we provide an update on MSI-related solid tumors with special focus on the predictive role of MSI for checkpoint immunotherapy.

Sox10 and S100 in the diagnosis of soft-tissue neoplasms.

Abstract: Despite a well-characterized lack of specificity, pathologists routinely employ S100 in the diagnosis of neural crest-derived tumors. Recent studies have shown that Sox10 is a reliable marker of neural crest differentiation that is consistently expressed in schwannian and melanocytic tumors. We sought to validate these results in a larger series of soft tissue neoplasms of both neural crest and non-neural crest origin, and to further characterize the sensitivity and specificity of Sox10 for use in clinical diagnosis. We evaluated Sox10 and S100 mRNA levels in 122 cases of peripheral nerve sheath tumors and synovial sarcoma and used immunohistochemistry for Sox10 and S100 protein expression in 1012 tissue specimens. This study includes 174 tissue microarray cases previously reported by Nonaka and colleagues, which include cases of melanoma, dermatofibrosarcoma protuberans, neurofibroma, synovial sarcoma, clear-cell sarcoma, malignant peripheral nerve sheath tumor (MPNST), perineurioma, and schwannoma. Synovial sarcomas expressed significantly higher levels of S100B than Sox10 (P=7.9×10), and no significant Sox10 mRNA expression was identified in synovial sarcoma (n=40), whereas 18/40 cases showed comparatively increased levels of S100 mRNA. The majority of schwannomas (n=26) and neurofibromas (n=28) showed relatively an increased expression of both Sox10 and S100 mRNA. MPNSTs (n=28) showed variable levels of Sox10 and S100 mRNA expression, and these expression levels were highly correlated (Pearson correlation coefficient r=0.79). In contrast, immunohistochemistry performed on a larger and more varied number of cases highlighted significant differences between the 2 proteins. We identified 5 non-neural, nonmelanocytic sarcoma types in which a subset of cases showed S100 protein expression: synovial sarcoma (12/79, 15%), Ewing sarcoma (3/14, 21%), rhabdomyosarcoma (4/17, 24%), chondrosarcoma (3/4, 75%), and extraskeletal myxoid chondrosarcoma (5/11, 45%). For each of these entities, we identified cases with strong and diffuse S100 staining. Of these cases, only 1 case of rhabdomyosarcoma showed focal Sox10 positivity. In 78 cases of MPNST, S100 increased the sensitivity (31/78, 40%) as compared with Sox10 (21/78, 27%), but the majority of these cases were negative for both Sox10 and S100 (44/78, 56%). Sox10 proved superior to S100 in the detection of desmoplastic melanoma (7/9, 78%) and clear-cell sarcoma (4/7, 57%). We also report for the first time Sox10 expression in 26 cases of granular cell tumor, further supporting the neural crest derivation of this tumor. Excluding MPNST, S100 and Sox10 showed similar sensitivity in tumors of neural crest origin (140/148, 95% and 137/148, 93%, respectively). In summary, Sox10 shows an increased specificity for tumors of neural crest origin compared with S100: Sox10 was positive in only 5 of 668 cases (99% specificity) in nonschwannian, nonmelanocytic tumors, whereas S100 was positive in 53 of 668 cases (91% specificity). Sox10 should be used in the place of or along with S100 in soft tissue tumor diagnosis.

Recommendations for improved standardization of immunohistochemistry.

Abstract: Immunohistochemistry (IHC) continues to suffer from variable consistency, poor reproducibility, quality assurance disparities, and the lack of standardization resulting in poor concordance, validation, and verification. This document lists the recommendations made by the Ad-Hoc Committee on Immunohi