Trastuzumab in combination with capecitabine or 5-fluorouracil and cisplatin is approved by the European Medicines Agency for the treatment of patients with human epidermal growth factor receptor 2 ...(HER2)-positive (immunohistochemistry 3+ or immunohistochemistry 2+/fluorescence in situ hybridization-positive or immunohistochemistry 2+/silver in situ hybridization-positive) metastatic adenocarcinoma of the stomach or gastro–esophageal junction. Approvals are underway in other countries, with recent approvals granted in the United States and Japan. Experience and data from trastuzumab use in breast cancer have highlighted the importance of quality HER2 testing and scoring to ensure accurate identification of patients eligible for treatment. HER2 testing in gastric cancer differs from testing in breast cancer due to inherent differences in tumor biology; gastric cancer more frequently shows HER2 heterogeneity (focal staining) and incomplete membrane staining. Consequently, gastric cancer-specific HER2 testing protocols have been developed and standardized and it is imperative that these recommendations be adhered to. Given the predictive value of HER2 protein levels with response in the trastuzumab for GAstric cancer study (ToGA), immunohistochemistry should be the initial testing methodology and fluorescence in situ hybridization or silver in situ hybridization should be used to retest immunohistochemistry 2+ samples. Wherever possible, bright-field methodologies should be used as these are considered to be superior to fluorescent methodologies at identifying heterogeneous staining. Specific training is required before embarking on HER2 testing in gastric cancer, irrespective of the experience of HER2 testing in breast cancer. This paper provides the most up-to-date practical guidance on HER2 testing and scoring in patients with gastric and gastro–esophageal junction cancer, as agreed by a panel of expert pathologists with extensive experience of HER2 testing particularly reflecting the European Medicines Agency-approved indication. It is anticipated that these recommendations should ensure accurate and consistent HER2 testing, which will allow appropriate selection of patients eligible for treatment with trastuzumab.
Leandro Luongo de Matos, Damila Cristina Trufelli, Maria Graciela Luongo de Matos and Maria Aparecida da Silva PinhalBiochemistry Department, Faculdade de Medicina do ABC, Santo André, SP, Brazil. ...AbstractThe immunohistochemistry technique is used in the search for cell or tissue antigens that range from amino acids and proteins to infectious agents and specific cellular populations. The technique comprises two phases: (1) slides preparation and stages involved for the reaction; (2) interpretation and quantification of the obtained expression. Immunohistochemistry is an important tool for scientific research and also a complementary technique for the elucidation of differential diagnoses which are not determinable by conventional analysis with hematoxylin and eosin. In the last couple of decades there has been an exponential increase in publications on immunohistochemistry and immunocytochemistry techniques. This review covers the immunohistochemistry technique; its history, applications, importance, limitations, difficulties, problems and some aspects related to results interpretation and quantification. Future developments on the immunohistochemistry technique and its expression quantification should not be disseminated in two languages-that of the pathologist and another of clinician or surgeon. The scientific, diagnostic and prognostic applications of this methodology must be explored in a bid to benefit of patient. In order to achieve this goal a collaboration and pooling of knowledge from both of these valuable medical areas is vital.
Loss of the CDKN2A gene and its protein p16 is a common event in pleural mesothelioma, which is frequently investigated to confirm the diagnosis. The loss of CDKN2A is often accompanied by ...simultaneous loss of the genes located in the vicinity, including the MTAP gene and protein. Detection of CDKN2A loss is usually achieved by relatively expensive fluorescent in situ hybridization (FISH) analysis. Here, we investigated if inexpensive immunohistochemistry (IHC) for p16 and MTAP could be used as an alternative detection method. Comparing CDKN2A and MTAP gene status, analyzed by the copy-number variation array, with p16/MTAP IHC revealed high sensitivity and specificity of the IHC for detecting gene loss. Our data show that p16/MTAP IHC can be used as an alternative to p16 FISH for detection of CDKN2A/MTAP loss. We recommend combined MTAP and p16 immunohistochemistry to confirm the diagnosis of PM. CDKN2A deletion is a common alteration in pleural mesothelioma (PM) and frequently associated with co-deletion of MTAP. Since the standard detection method for CDKN2A deletion and FISH analysis is relatively expensive, we here investigated the suitability of inexpensive p16 and MTAP IHC by comparing concordance between IHC and OncoScan CNV arrays on samples from 52 PM patients. Concordance was determined using Cohen’s kappa statistics. Loss of CDKN2A was associated with co-deletion of MTAP in 71% of cases. CDKN2A-MTAP copy-number normal cases were also IHC positive in 93% of cases for p16 and 100% for MTAP, while homozygous deletion of CDKN2A-MTAP was always associated with negative IHC for both proteins. In cases with heterozygous CDKN2A-MTAP loss, IHC expression of p16 and MTAP was negative in 100% and 71%, respectively. MTAP and p16 IHC showed high sensitivity (MTAP 86.5%, p16 100%) and specificity (MTAP 100%, p16 93.3%) for the detection of any gene loss. Loss of MTAP expression occurred exclusively in conjunction with loss of p16 labeling. Both p16 and MTAP IHC showed high concordance with Oncoscan CNV arrays (kappa = 0.952, p < 0.0001, and kappa = 0.787, p < 0.0001 respectively). We recommend combined MTAP and p16 immunohistochemistry to confirm the diagnosis of PM.
Duodenal Neuroendocrine Tumours (D-NETs) are extremely rare tumours with a propensity to be solitary and limited to the first and second parts of the duodenum, the periampullary area contributing to ...only about 20% of such cases. They can be discovered incidentally at imaging or at Upper Gastrointestinal Endoscopy (UGIE) for vague Gastrointestinal (GI) symptoms. The authors encountered two successive cases (55-year-old female; 50-year-old male) of D-NETs within a couple of months in which one presented with acute upper GI bleeding and another with vague upper GI symptoms. The first case was located at the second part of the duodenum with nodal metastasis, whilst the second case had multiple D-NETs at the second and third parts of the duodenum. Sub-centimetric growths may be treated by endoscopic mucosal resections but larger ones require surgery. Both cases were more than 20 mm in size and were successfully managed by classical Whipple’s procedure. Diagnoses were confirmed and graded with histopathology and Immunohistochemistry (IHC) using chromogranin, synaptophysin, and Kiel 67 (Ki67). Normally these are mucosal and submucosal lesions, however, in the first case, the tumour invaded muscularis propria and extended upto subserosa. The authors present these two cases because of their rarity, singular presentations, and successful management in a rural set-up with logistical constraints.
Schwannomas are common benign tumours arising from the myelin sheath of peripheral nerves. These tumours are usually located in the intradural and extramedullary regions. The common sites are ...cervical (58%) and thoracic region (32%), followed by the lumbar region (10%). Intramedullary location is rare and if present, is usually associated with neurofibromatosis 1 and 2 (NF-1 and 2). Intramedullary brainstem schwannomas without NF are uncommon, and to the best of the authors’ knowledge, only 19 cases have been reported to date. It was first described by James Watson Kernohan, an Irish-American pathologist, in 1931. The rarity of these tumours in this location is due to the absence of Schwann cells in this area. There are several hypotheses postulating the presence of these tumours in this location. The exact cause is not yet known. The authors here present a case of intramedullary brainstem ancient schwannoma with an unusual clinicoradiological presentation, which raised suspicion of Glioma with the possibility of Astrocytoma. The patient presented with right-sided neck stiffness and shoulder pain for a period of four months. Total excision of the tumour was performed, and the postoperative period was uneventful with clinical improvement in the patient. Histomorphology raised the suspicion of a tumour of glial origin with the possibility of Astrocytoma; Immunohistochemistry (IHC) helped in reaching the definitive diagnosis of Ancient Schwannoma. Thus, a combined approach of clinicoradiological, as well as histomorphology and IHC, is essential for a definitive diagnosis of these tumours. Future multicentric studies are required to elucidate the pathogenesis of the location of these tumours.
Renal tumors: diagnostic and prognostic biomarkers Tan, Puay Hoon; Cheng, Liang; Rioux-Leclercq, Nathalie ...
The American journal of surgical pathology,
2013-October, Letnik:
37, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The International Society of Urological Pathology convened a consensus conference on renal cancer, preceded by an online survey, to address issues relating to the diagnosis and reporting of renal ...neoplasia. In this report, the role of biomarkers in the diagnosis and assessment of prognosis of renal tumors is addressed. In particular we focused upon the use of immunohistochemical markers and the approach to specific differential diagnostic scenarios. We enquired whether cytogenetic and molecular tools were applied in practice and asked for views on the perceived prognostic role of biomarkers. Both the survey and conference voting results demonstrated a high degree of consensus in participants' responses regarding prognostic/predictive markers and molecular techniques, whereas it was apparent that biomarkers for these purposes remained outside the diagnostic realm pending clinical validation. Although no individual antibody or panel of antibodies reached consensus for classifying renal tumors, or for confirming renal metastatic disease, it was noted from the online survey that 87% of respondents used immunohistochemistry to subtype renal tumors sometimes or occasionally, and a majority (87%) used immunohistochemical markers (Pax 2 or Pax 8, renal cell carcinoma RCC marker, panel of pan-CK, CK7, vimentin, and CD10) in confirming the diagnosis of metastatic RCC. There was consensus that immunohistochemistry should be used for histologic subtyping and applied before reaching a diagnosis of unclassified RCC. At the conference, there was consensus that TFE3 and TFEB analysis ought to be requested when RCC was diagnosed in a young patient or when histologic appearances were suggestive of the translocation subtype; whereas Pax 2 and/or Pax 8 were considered to be the most useful markers in the diagnosis of a renal primary.
The visualization of molecularly labeled structures within large intact tissues in three dimensions is an area of intense focus. We describe a simple, rapid, and inexpensive method, iDISCO, that ...permits whole-mount immunolabeling with volume imaging of large cleared samples ranging from perinatal mouse embryos to adult organs, such as brains or kidneys. iDISCO is modeled on classical histology techniques, facilitating translation of section staining assays to intact tissues, as evidenced by compatibility with 28 antibodies to both endogenous antigens and transgenic reporters like GFP. When applied to degenerating neurons, iDISCO revealed unexpected variability in number of apoptotic neurons within individual sensory ganglia despite tight control of total number in all ganglia. It also permitted imaging of single degenerating axons in adult brain and the first visualization of cleaved Caspase-3 in degenerating embryonic sensory axons in vivo, even single axons. iDISCO enables facile volume imaging of immunolabeled structures in complex tissues. PAPERCLIP:
Aims
The most commonly mutated gene in vulvar squamous cell carcinoma (VSCC) is TP53 and its prognostic value, particularly in HPV‐independent VSCC, is uncertain. In other tumours, p53 ...immunohistochemistry (IHC) is an excellent surrogate marker for TP53 mutations. In order to study this in VSCC, we assigned six p53 IHC patterns into two final classes: ‘wild‐type’ or ‘mutant’. We determined the performance and interobserver variability of this pattern‐based p53 IHC approach.
Methods and results
Two experienced gynaecological pathologists scored the predefined p53 IHC patterns of 59 VSCC, independently and blinded for molecular data. Agreement was calculated by Cohen's kappa. All disagreements regarding p53 IHC patterns were resolved by a consensus meeting. After DNA isolation, the presence of pathogenic TP53 variants was determined by next‐generation sequencing (NGS). Sensitivity, specificity and accuracy of p53 IHC as a surrogate marker for TP53 mutation status were calculated. Initial p53 IHC pattern interpretation showed substantial agreement between both observers (k = 0.71, P < 0.001). After consensus, 18 cases (30.5%) were assigned a final p53 IHC class as TP53 wild‐type and 41 cases (69.5%) as mutant. The accuracy between the p53 IHC class and TP53 mutation status, after the consensus meeting, was 96.6%. Moreover, the sensitivity and specificity were high 95.3% 95% confidence interval (CI) = 82.9–99.1% and 100% (95% CI = 75.9–100%).
Conclusions
Pattern‐based p53 IHC classification is highly reproducible among experienced gynaecological pathologists and accurately reflects TP53 mutations in VSCC. This approach to p53 IHC interpretation offers guidance and provides necessary clarity for resolving the proposed prognostic relevance of final p53 IHC class within HPV‐independent VSCC.
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