Applied Immunohistochemistry & Molecular Morphology最新文献

Immunohistochemistry (IHC), also referred to as immunocytochemistry in cytology literature, has revolutionized the practice of cytopathology. Because of the complexity of cytology preparation and limited diagnostic material, performing IHC remains a challenge. Formalin-fixed paraffin-embedded (FFPE) cell block (CB) is the optimal choice for IHC. In this review, the approaches for improving CB preparation will be discussed. When CB material is not available, various cytology specimens can also be used for IHC. With the utilization of Antigen Retrieval (AR) technique, these nonformalin-fixed cytology specimens can achieve successful IHC staining, comparable with the results from FFPE tissue sections. In the last part of this review, we will discuss the use of positive controls and the important role of AR in standardization of IHC in cytology.

Starting in the mid-1970s, we formed a group of pathologists with a major interest in uropathology. Originally, it included 2 (R.M. and M.S.). In the years the followed, the group was enlarged to include 4 more people, 2 in the mid- and late-1980s (A.L.B. and L.C.) and another in the mid-1990s (R.Ma.); a sixth (A.C.) joined the group ∼5 years ago. Two have reached the retirement age (R.M. and M.S.), while others are in the process of joining the group to replace them. A fruitful collaboration spanned for ∼45 years. This contribution is based on a series of personal recollections of the successive changes in the interpretation of prostate cancer and its precursors, starting in the mid-1970s. Here we have retraced our involvement steps, sharing issues related to them with a junior uropathologist (A.C.).

This review is based on a webinar I presented for the International Society for Immunohistochemistry and Molecular Morphology (ISIMM) in February 2022. It is intended that all ISIMM webinars will ultimately be published in AIMM as review articles. This work is also dedicated to Clive Taylor, who has deeply impacted my career. It presents a molecularly informed, pattern-based approach to p53 immunohistochemistry interpretation, methodological considerations (ie, antibody selection, optimization, validation, controls, and external quality assessment), and pan-cancer diagnostic applications, including those drawn from gastrointestinal, genitourinary, gynecological, neuroendocrine, hematologic, and neuropathology. It intends to prove the thesis statement that p53 is an exemplar next-generation immunohistochemical marker "born" ahead of its time.

Magee equations (MEs) are a set of multivariable models that were developed to estimate the actual Onco type DX (ODX) recurrence score in invasive breast cancer. The equations were derived from standard histopathologic factors and semiquantitative immunohistochemical scores of routinely used biomarkers. The 3 equations use slightly different parameters but provide similar results. ME1 uses Nottingham score, tumor size, and semiquantitative results for estrogen receptor (ER), progesterone receptor, HER2, and Ki-67. ME2 is similar to ME1 but does not require Ki-67. ME3 includes only semiquantitative immunohistochemical expression levels for ER, progesterone receptor, HER2, and Ki-67. Several studies have validated the clinical usefulness of MEs in routine clinical practice. The new cut-off for ODX recurrence score, as reported in the Trial Assigning IndividuaLized Options for Treatment trial, necessitated the development of Magee Decision Algorithm (MDA). MEs, along with mitotic activity score can now be used algorithmically to safely forgo ODX testing. MDA can be used to triage cases for molecular testing and has the potential to save an estimated $300,000 per 100 clinical requests. Another potential use of MEs is in the neoadjuvant setting to appropriately select patients for chemotherapy. Both single and multi-institutional studies have shown that the rate of pathologic complete response (pCR) to neoadjuvant chemotherapy in ER+/HER2-negative patients can be predicted by ME3 scores. The estimated pCR rates are 0%, <5%, 14%, and 35 to 40% for ME3 score <18, 18 to 25, >25 to <31, and 31 or higher, respectively. This information is similar to or better than currently available molecular tests. MEs and MDA provide valuable information in a time-efficient manner and are available free of cost for anyone to use. The latter is certainly important for institutions in resource-poor settings but is also valuable for large institutions and integrated health systems.

Immunohistochemistry (IHC) is a testing methodology that is widely used for large number of diagnostic, prognostic, and predictive biomarkers. Although IHC is a qualitative methodology, in addition to threshold-based stratification (positive vs. negative), the increasing levels of expression of some of these biomarkers often lead to more intense staining, which published evidence linked to specific diagnosis, prognosis, and responses to therapy. It is essential that the descriptive thresholds between positive and negative staining, as well as between frequently used graded categories of staining intensity (eg, 1+, 2+, 3+) are standardized and reproducible. Histo-score (H-score) is a frequently used scoring system that utilizes these categories. Our study introduces categorization of the cutoff points between positive and negative results and graded categories of staining intensity for nuclear IHC biomarker assays based on color interaction between hematoxylin and diaminobenzidine (DAB); the Blue-brown Color H-score (BBC-HS). Six cases of diffuse large B-cell lymphoma were stained for a nuclear marker MUM1. The staining was assessed by H-score by 12 readers. Short tutorial and illustrated instructions were provided to readers. The novel scoring system in this study uses the interaction between DAB (DAB, brown stain) and hematoxylin (blue counterstain) to set thresholds between "0" (negative nuclei), "1+" (weakly positive nuclei), "2+" (moderately positive nuclei), and "3+" (strongly positive nuclei). The readers recorded scores for 300 cells. Krippendorff alpha (K-alpha) and intraclass correlation coefficient (ICC) were calculated. We have also assessed if reliability improved when counting the first 100 cells, first 200 cells, and for the total 300 cells using K-alpha and ICC. To assess the performance of each individual reader, the mean H-score and percent positive score (PPS) for each case was calculated, and the bias was calculated between each reader's score and the mean. K-alpha was 0.86 for H-score and 0.76 for PPS. ICC was 0.96 for H-score and 0.92 for PPS. The biases for H-score ranged from -58 to 41, whereas for PPS it ranged from -27% to 33%. Overall, most readers showed very low bias. Two readers were consistently underscoring and 2 were consistently overscoring compared with the mean. For nuclear IHC biomarker assays, our newly proposed cutoffs provide highly reliable/reproducible results between readers for positive and negative results and graded categories of staining intensity using existing morphologic parameters. BBC-HS is easy to teach and is applicable to both human eye and image analysis. BBC-HS application should facilitate the development of new reliable/reproducible scoring schemes for IHC biomarkers.

Typically, myeloma cells express a monoclonal immunoglobulin (Ig), either heavy or light chain. Here, we present a case of multiple myeloma with clonal dual expression of kappa and lambda light chain in a 74-year-old woman. Awareness of rare biphenotypic myeloma is important for proper diagnostic workup. A 74-year-old woman underwent hip replacement with an incidental finding of 20% plasma cells in the femoral head. Subsequent bone marrow biopsy also showed about 30% of plasma cells negative for CD20, CD56, and CD117. Immunohistochemistry (IHC) and in situ hybridization studies showed a mixture of kappa and lambda plasma cells. Flow cytometry showed ambiguous results for cytoplasmic Ig light chains kappa and lambda. However, cyclin D1 was highly expressed by plasma cells, and increased free kappa light chains were identified in serum. Further investigation by double IHC demonstrated co-expression of kappa and lambda light chains in the same cells. Fluoresces in situ hybridization studies were positive for t(11;14)(q13;q32) and the deletion 13q. Since its first description by Taylor and Burns in 1974, the demonstration of restricted cytoplasmic Ig light chain expression by immunohistochemistry is 1 of the basic tools for corroborating clonality of the plasma cells in tissue biopsy. IHC results in myeloma with dual expression of Ig light chains may suggest polyclonal plasma cell population, especially when plasma cells do not form sheets in the bone marrow. In an appropriate clinical setting, other investigations are needed to exclude plasma cell neoplasm, even with seemingly "polytypic" results by IHC.

Crooke cell change was first found in the regressed and suppressed corticotroph (adrenocorticotropic hormone-producing) cells, and now is known to occur in pituitary tumors. The tumor cells of this type can be recognized by morphology with immunohistochemistry, and are well known to predict aggressive behavior such as invasion and rare metastases. This is one of the representative neuroendocrine tumors in the pituitary which is now considered to have malignant potential as proposed in the pancreas and gastrointestinal tracts. It is important to emphasize the pituitary tumor pathology such as Crooke cell change for prognostication and appropriate therapies. This review article describes the evolution from the Crooke cells to Crooke cell tumors which is timely along with the Fifth WHO classification 2022 published online.

Ki-67 is a nuclear protein serendipitously discovered by monoclonal antibody selection in the early 1980s. While it has been applied for decades in the context of breast cancer as a putative prognostic and, more recently, predictive, biomarker, even after all this time there is incomplete agreement as to the validity of the immunohistochemical assays employed for Ki-67 assessment, given possible effects of the disparate methodologies employed and possible confounding preanalytical, analytical, and interpretive variables. In this brief review, the history of Ki-67 and the problems, particularly with the analytical and interpretive variables, are highlighted through a selective review of the published literature. The contributions of the International Ki-67 Breast Cancer Working Group are highlighted, and in particular, the recommendations made by this group are reviewed. The potential of Ki-67 as a biomarker for breast cancer has not yet been fully realized, but an understanding of the power as well as the limitations of the methods of Ki-67 assessment are important if this biomarker can realize its potential.