Novel quantitative immunohistochemistry method using histone H3, family 3B as the internal reference standard for measuring human epidermal growth factor receptor 2 expression in breast cancer

BACKGROUND

Immunohistochemistry (IHC) is an essential technique in surgical and clinical pathology for detecting diagnostic, prognostic, and predictive biomarkers for personalized cancer therapy. However, the lack of standardization and reference controls results in poor reproducibility, and a reliable tool for IHC quantification is urgently required. The objective of this study was to describe a novel approach in which H3F3B (histone H3, family 3B) can be used as an internal reference standard to quantify protein expression levels using IHC.

METHODS

The authors enrolled 89 patients who had human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC). They used a novel IHC-based assay to measure protein expression using H3F3B as the internal reference standard. H3F3B was uniformly expressed at the protein level in all tumor regions in cancer tissues. HER2 expression levels were measured with the H-score using HALO software.

RESULTS

Kaplan-Meier analysis indicated that, among patients who had HER2-positive BC in The Cancer Genome Atlas data set and the authors' data set, the subgroup with low HER2 expression had a significantly better prognosis than the subgroup with high HER2 expression. Furthermore, the authors observed that HER2 expression levels were precisely evaluated using the proposed method, which can classify patients who are at higher risk of HER2-positive BC to receive trastuzumab-based adjuvant therapy. Dual-color IHC with H3F3B is an excellent tool for internal and external quality control of HER2 expression assays.

CONCLUSIONS

The proposed IHC-based quantification method accurately assesses HER2 expression levels and provides insights for predicting clinical prognosis in patients with HER2-positive BC who receive trastuzumab-based adjuvant therapy.

Prognostic value of tumor immune microenvironment factors in patients with stage I lung adenocarcinoma

Survival is difficult to predict in patients with resected stage I lung adenocarcinoma (LUAD), but tumor microenvironment (TME) factors appear useful in predicting survival in advanced non-small cell lung cancer. We aimed to identify the TME factors linked to recurrence/metastasis and survival in stage I LUAD patients. We evaluated TME factors in stage I LUAD patients in The Cancer Genome Atlas (TCGA) using the "ESTIMATE" and "MCP-counter" R packages. We characterized infiltrating immune cells in the tumor and stromal regions in 44 stage I LUAD patients at our hospital using immunohistochemical methods combined with the HALO^® Image Analysis Platform. In TCGA LUAD patients, the number of neutrophils was higher in patients without recurrence/metastasis than in patients with recurrence/metastasis. For patients with recurrence/metastasis, higher CD8+ T lymphocyte and B lymphocyte infiltration levels were associated with better overall survival (OS), and myeloid dendritic cell (DC) infiltration was associated with better disease-free survival (DFS). In stage I LUAD patients at our hospital, CD4+ T cells, CD8+ T cells, CD14+ monocytic lineage cells, CD16+ NK cells, and CD19+ B lymphocytes were more highly expressed in stromal regions than in tumor regions. Moreover, high intratumoral CD11c+ myeloid DC and CD68+ macrophage levels were associated with recurrence/metastasis. Within tumor regions, higher CD11c+ myeloid DC and CD68+ macrophage levels were associated with shorter DFS; within stromal regions, higher CD68+ macrophage levels were associated with shorter DFS. Multivariate analysis revealed that the presence of intravascular carcinoma embolus, higher intratumoral CD11c+ myeloid DC levels, and high stromal CD68+ macrophage and CD4+ T-cell levels were independently linked to recurrence/metastasis in stage I LUAD patients. This study using 2 datasets shows that key players in the TME are associated with recurrence/metastasis in stage I LUAD patients. Higher intratumoral CD11c+ myeloid DC, stromal CD68+ macrophage and stromal CD4+ T-cell levels are independent prognostic factors for DFS in these patients.

Multiplex Immunohistochemistry Analysis of Melanoma Tumor-Infiltrating Lymphocytes

Tumor-infiltrating lymphocytes (TILs) are an important prognostic indicator in melanoma and play a key role in the patient's response to immune checkpoint blockade. However, until recently, it was not possible to combine multi-parameter markers to define the TILs and their histological context. Multiplex immunohistochemistry (mIHC) is a new technology which addresses this issue and enables simultaneous detection of melanoma and multiple immune subsets in formalin fixed paraffin embedded tissue. Following antigen retrieval, melanoma tissue sections are stained by OPAL on an autostainer, including serial rounds of epitope labelling with monoclonal antibodies followed by tyramide signal amplification (TSA). The stained tissue sections are then imaged on the Vectra instrument, and digital images are processed by analysis software (inForm and HALO) to derive tissue segmentation and immune subset densities within the tumor and tumor stroma. Spatial relationships between immune cells and tumor cells are then analyzed using a novel R algorithm. Taken together, multiplex IHC describes the histological context of the immune system in melanoma. The data is objective and allows for characterization of individual melanomas as T cell inflamed (hot), immune excluded, or no immune cells (cold).

Overcoming Autofluorescence (AF) and Tissue Variation in Image Analysis of In Situ Hybridization

Fluorescent detection of nucleic acid sequences such as DNA or RNA allows for multiplexing and visualization of an increased number of targets compared with chromogenic methods. This is due to the number of chromogens available as well as the ability of image analysis software platforms to distinguish between colors. Autofluorescence (AF) can be problematic during fluorescent imaging because the AF interferes with the detection of the specific fluorescent signals especially when the target signals are weak. AF has a broad emission spectrum leading to difficulty when performing image analysis due to masking of the specific signal across multiple wavelengths. Tissue sample variation can also affect levels of AF. In this chapter we share a method for overcoming the issues caused by sample variation and AF using HALO software on RNAscope in situ hybridization images.

Why HALO 301 Failed and Implications for Treatment of Pancreatic Cancer

Survival rates for pancreatic cancer (PC) remain dismal. Current standard of care treatment regimens provide transient clinical benefit but eventually chemoresistance develops leading to poor outcomes. PC is a relatively chemoresistant tumor and one of the explanations for this is attributed to desmoplasia that impedes drug delivery. Based on this, stromal modifying agent such as Pegvorhyaluronidase alfa (PEGPH20) was developed and investigated in phase I-III studies. Although phase I-II studies showed promising results in patients with high hyaluronic acid (HA) expressing tumors, the phase III HALO 301 study failed to miss it’s primary endpoint and further development of PEHPH20 is halted. This failure implies that targeting desmoplasia alone is not sufficient and other intrinsic factors such as lack of significant neoantigens, low tumor mutational burden, and epithelial to mesenchymal transition may be at play. It is also important to consider that although the tumor stroma may be a physical barrier hampering drug delivery, it may also have protective effects in restraining tumor growth and progression. Further studies in molecular biology to better characterize the complex interaction between the microenvironment and cancer cells are warranted.

Quantification of histopathological findings using a novel image analysis platform

Digital pathology, including image analysis and automatic diagnosis of pathological tissue, has been developed remarkably. HALO is an image analysis platform specialized for the study of pathological tissues, which enables tissue segmentation by using artificial intelligence. In this study, we used HALO to quantify various histopathological changes and findings that were difficult to analyze using conventional image processing software. Using the tissue classifier module, the morphological features of degeneration/necrosis of the hepatocytes and muscle fibers, bile duct in the liver, basophilic tubules and hyaline casts in the kidney, cortex in the thymus, and red pulp, white pulp, and marginal zone in the spleen were learned and separated, and areas of interest were quantified. Furthermore, using the cytonuclear module and vacuole module in combination with the tissue classifier module, the number of erythroblasts in the red pulp of the spleen and each area of acinar cells in the parotid gland were quantified. The results of quantitative analysis were correlated with the histopathological grades evaluated by pathologists. By using artificial intelligence and other functions of HALO, we recognized morphological features, analyzed histopathological changes, and quantified the histopathological grades of various findings. The analysis of histopathological changes using HALO is expected to support pathology evaluations.

Advances in targeted degradation of endogenous proteins

Protein silencing is often employed as a means to aid investigations in protein function and is increasingly desired as a therapeutic approach. Several types of protein silencing methodologies have been developed, including targeting the encoding genes, transcripts, the process of translation or the protein directly. Despite these advances, most silencing systems suffer from limitations. Silencing protein expression through genetic ablation, for example by CRISPR/Cas9 genome editing, is irreversible, time consuming and not always feasible. Similarly, RNA interference approaches warrant prolonged treatments, can lead to incomplete protein depletion and are often associated with off-target effects. Targeted proteolysis has the potential to overcome some of these limitations. The field of targeted proteolysis has witnessed the emergence of many methodologies aimed at targeting specific proteins for degradation in a spatio-temporal manner. In this review, we provide an appraisal of the different targeted proteolytic systems and discuss their applications in understanding protein function, as well as their potential in therapeutics.

Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the endoscopic tools to recognize squamous cell dysplasia; confocal laser endomicroscopy for Barrett's esophagus; confocal microscopy in the cancer patient; optical coherence tomography in the assessment of subsquamous Barrett's metaplasia; endoscopic mucosal resection for high-grade dysplasia in Barrett's esophagus; HALO in the treatment of squamous dysplasia; and the use of fluorescence in situ hybridization to detect dysplasia and adenocarcinoma in patients with Barrett's esophagus.