Gastrin Staining in Inflamed Stomach Biopsies Labeled as "Antral" Rarely Detects Atrophic Gastritis.

OBJECTIVES: Autoimmune metaplastic atrophic gastritis (AMAG) is an underrecognized entity, especially in its early stage. This study assessed whether the use of gastrin immunohistochemistry would increase sensitivity for diagnosing early AMAG. METHODS: Three-hundred gastric biopsies were prospectively stained for gastrin by immunohistochemistry. Inclusion criteria included well-oriented gastric mucosa with mucus glands and minimal plasma cell infiltrate not suspected to represent pyloric metaplasia. Patient age, sex, designated location of biopsy, presence or absence of intestinal metaplasia, and clinical information were not criteria. Any case with absence of gastrin-positive endocrine cells reflexed to chromogranin immunohistochemistry. Maloriented biopsies or cases with current Helicobacter infection were excluded. RESULTS: The 298-patient study cohort comprised 222 females (mean age, 47 years; range, 16-80 years) and 76 males (mean age, 49 years; range, 7-80 years). Biopsies were designated as "antral/antral nodules" (61%), and the rest were labeled "gastric/random stomach" (39%). Nine cases (3%) exhibited absence of gastrin-positive endocrine cells; one of those showed endocrine cell hyperplasia by chromogranin staining. CONCLUSIONS: Pathologists should be aware of the histologic features of early AMAG and meticulously analyze tissue regardless of specimen labeling. Gastrin immunostain is a supplemental diagnostic tool when encountering inflamed antral-appearing specimens.

IMP3 Immunohistochemical Expression Remains Consistent Among All Grades of Gastrointestinal Neuroendocrine Tumors.

Insulin-like growth factor-II messenger RNA-binding protein-3 (IMP3), is an oncofetal protein whose aberrant expression has previously been detected in multiple malignant neoplasms. Pulmonary neuroendocrine carcinomas demonstrate increased expression compared with pulmonary carcinoid tumors, but this relationship has not been studied in gastrointestinal neuroendocrine tumors (GINETs). This study examined IMP3 expression in GINETs, with a focus on correlation with established grading criteria. Fifty-four GINETs were immunohistochemically studied using a monoclonal antibody against IMP3. Using established World Health Organization criteria, the cases were stratified by grade and included 31 grade 1 neuroendocrine tumors (G1 GINETs), 15 grade 2 neuroendocrine tumors (G2 GINETs), and 8 neuroendocrine carcinomas (GINECs). The majority (51/54, 94.4%) of GINETs demonstrated IMP3 staining. Thirty cases (55.6%) showed IMP3 cytoplasmic/membranous staining in 60% or greater of tumor cells, with moderate to strong staining in nearly all of these cases (29/30; 96.7%). Of the remaining 24 cases, 3 cases showed no staining, whereas 17 (81%) demonstrated weak staining. When stratified by grade, there was no statistically significant difference in IMP3 staining among the 3 grades of GINETs; of the G1 GINETs, 14 (45.2%) demonstrated staining in at least 60% of tumor cells, compared with 10 (66.7%) G2 GINETs and 6 (75%) GINECs. Hindgut neoplasms of any grade were the most likely to show significant IMP3 staining. Unlike what has been demonstrated in neuroendocrine neoplasms in the lungs, GINETs appear to have a consistent IMP3 expression profile among all tumors grades, which may be reflective of their unique tumor biology.

Gastric Carcinomas With Lymphoid Stroma: Categorization and Comparison With Solid-Type Colonic Carcinomas.

OBJECTIVES: To determine whether histologic features could help identify gastric carcinomas with lymphoid stroma associated with microsatellite instability (MSI) (ie, "medullary carcinomas"), Epstein-Barr virus (EBV) infection (termed lymphoepithelioma-like carcinomas in other organ systems), or neither. METHODS: We identified 17 solid-type gastric carcinomas with lymphoid stroma, assessed EBV and MSI status, and compared features across groups. We also compared them with 51 solid-type colorectal adenocarcinomas. RESULTS: In the stomach, EBV-associated carcinomas (n = 8) contained intratumoral germinal centers (P = .024) and eosinophils (P = .030) and lacked necrosis (P = .019) compared with MSI-associated carcinomas (n = 5) and non-EBV, non-MSI carcinomas (n = 4). In the colon, MSI-driven carcinomas (n = 40) more frequently contained intratumoral lymphocytes (P = .017) and neutrophils (P = .0050) and less often metastasized to distant sites (P = .0040) than poorly differentiated carcinomas lacking MSI (n = 11). CONCLUSIONS: Morphology may help classify gastric carcinomas with lymphoid stroma, although ancillary testing appears more reliable. Lymphoepithelioma-like carcinoma and medullary carcinoma should not be used interchangeably.

Chorionic Histiocytic Hyperplasia is Associated With Chronic Inflammatory Lesions in the Placenta.

Background Chorionic histiocytic hyperplasia (CHH) is a cellular proliferation at the base of the chorion that was identified by the authors in examining placentas for chronic chorioamnionitis (CC). This study is a retrospective review of cases diagnosed with CHH, describing its incidence alone and with associated lesions, and the immunophenotype of lesional cells. Design In this retrospective study, a laboratory information system search over a 34-month period using the key phrase "chorionic stromal" was performed. Cases identified were reviewed for presence of the following: CC, chronic villitis (CV), chronic deciduitis (CD), maternal (MIR), and fetal (FIR) acute inflammatory responses, meconium deposition; and whether CD3 immunostaining was performed. Incidences were tabulated and compared with known prevalences in our population. Select cases were stained with various immunostains to identify cell lineage and X and Y fluorescent probes to identify fetal or maternal cell origin in cases with male infants. Results Eighty cases of CHH were identified during the study period. Incidences of inflammatory lesions associated with CHH were: CV (54/80, 68%), CD (32/80, 40%), CC (25/80, 31%), MIR (39/80, 49%), and FIR (9/80, 11%). Only chronic inflammatory lesions had a significant correlation with the co-incidence of CHH. CC was identified alongside CHH in 12 of 22 cases in which a CD3 immunostain was performed. The cell population in CHH was vimentin+, CD68+, CD3-, CD45-, CD56-, hPL-, SMA-, OCT 3/4- and, in some cases, variably mixed with CD3+ lymphocytes. The cells had a male genotype by fluorescent in situ hybridization analysis. Conclusion The association of CHH with acute and chronic inflammatory conditions and its immunophenotype suggest that it may be a reactive process. CD3 immunostaining is helpful to identify concurrent CC.

Distinction between inflammatory hepatocellular adenoma and mass effect on liver sampling.

Inflammatory hepatocellular adenoma (IHA) is characterized by sinusoidal dilation, inflammation, and bile ductular reaction. However, these changes can also be seen in nonneoplastic liver tissue adjacent to a mass lesion. This differential may arise in biopsy tissue attempting to sample a liver mass. Serum amyloid A (SAA) immunostaining is useful for the diagnosis of IHA but is not entirely specific. In addition, the histologic pattern of mass effect (ME) has received little formal scrutiny. We compared the clinical, morphologic, and immunohistochemical findings in 18 IHA and 36 livers with ME. Several histologic findings were evaluated in all cases. SAA and CD34 staining were also performed. Patients with IHA were younger (P<.0001) and more often female (P=.0044) than patients with specimens showing ME, but lesions were multifocal on imaging in two-thirds of patients in each category. Unpaired arteries were only seen in IHA (P<.0001), whereas ductular reaction was more common in ME (P=.012). Strong SAA immunostaining was observed in 100% of IHAs and 56% of ME cases (P=.0004), and CD34 staining was seen in 95% of IHAs and 6% of ME cases (P<.0001). Unpaired arteries and staining for SAA and CD34 best distinguish IHA from ME. However, unpaired arteries may be absent because of sampling, and SAA is not available in all laboratories. Ductular reaction can occur in IHA but is more common in ME.

Immunohistochemistry as a surrogate for molecular subtyping of gastric adenocarcinoma.

The Cancer Genome Atlas Research Network recently classified gastric adenocarcinoma into 4 molecular subtypes: Epstein-Barr virus-positive tumors, microsatellite-unstable tumors, tumors with chromosomal instability, and genomically stable tumors. We theorized that immunohistochemistry might be useful in similar categorization and that that HER2 expression might relate to subtype. We stained 104 gastric adenocarcinomas for MLH1, p53, and EBER in situ hybridization. We grouped them based on staining pattern and compared the groups. Cases were categorized as follows: group 1 (EBER positive), 7 cases (7%); group 2 (MLH1 deficient), 17 cases (16%); group 3 (aberrant p53 staining, EBER negative, retained MLH1), 40 cases (38%); group 4 (unremarkable staining), 40 cases (38%). This distribution was comparable to that found by the Research Network after accounting for the TP53 mutation rate in the chromosomal instability group. Group 1 patients had significantly longer follow-up times (median, 70 months versus 13 months for other groups; P = .0324). No group 2 cases overexpressed HER2. In group 3, 3 of 40 cases were HER2 immunohistochemistry positive, but 7 of 27 were HER2 positive by fluorescence in situ hybridization. Staining offers an efficient, reasonably accurate alternative for molecular subtyping of gastric adenocarcinoma, although some cases with chromosomal instability cannot be identified. These findings have potential prognostic and therapeutic implications.

High frequency of coexpression of maspin with p63 and p53 in squamous cell carcinoma but not in adenocarcinoma of the lung.

Maspin, a member of the serpin family of protease inhibitors, has been shown to inhibit tumor growth and suppress metastasis in several malignancies, including lung cancer. Previous studies have reported that p63 and p53 control maspin expression by transactivating the promoter. The present study analyzed immunohistochemical studies to determine the expression and coexpression patterns of maspin, p63 and p53 in non-small cell lung carcinoma, specifically squamous cell carcinoma and adenocarcinoma. The results showed that 83/86 cases (96.5%) of squamous cell carcinoma and 82/161 cases (50.9%) of adenocarcinoma included in this study were positive for maspin. There were 79/86 cases (91.9%) of squamous cell carcinoma and 16/161 cases (9.9%) of adenocarcinoma with positive expression for p63. In addition, 77/86 cases (89.5%) of squamous cell carcinoma and 99/161 cases (61.5%) of adenocarcinoma were positive for p53. Maspin, p63 and p53 expression were each significantly higher in squamous cell carcinoma than adenocarcinoma. Squamous cell carcinomas more highly coexpress maspin and p63, as well as maspin and p53, when compared with adenocarcinomas. The high frequency of coexpression of maspin and p63, as well as maspin and p53, in squamous cell carcinoma, suggests that p63 and p53 may be involved in the pathway to control maspin expression. Therapeutic targeting on maspin, p63 and p53 molecules might be beneficial in the management of patients with squamous cell carcinomas of the lung in the future.

GATA binding protein 3 is down-regulated in bladder cancer yet strong expression is an independent predictor of poor prognosis in invasive tumor.

Although GATA binding protein 3, a zinc finger transcription factor and an estrogen receptor-regulated gene, has recently been suggested as a marker for urothelium, prognostic significance of GATA binding protein 3 expression in bladder tumor remains unclear. We immunohistochemically stained for GATA binding protein 3 in urothelial neoplasm and matched nonneoplastic bladder tissue specimens. GATA binding protein 3 was positive in 125 (86%; 13 [9%] weak, 44 [30%] moderate, and 68 [47%] strong) of 145 bladder tumors, which was significantly lower than in benign urothelium (104/106 [98%]; 3 [3%] weak, 30 [28%] moderate, and 71 [67%] strong) (P=.001). Fifty (98%) of 51 low-grade tumors were GATA binding protein 3 positive, whereas 75 (80%) of 94 high-grade carcinomas were GATA binding protein 3 positive (P=.002). Similarly, 78 (98%) of 80 non-muscle-invasive tumors expressed the GATA binding protein 3, compared with 47 (72%) of 65 muscle-invasive tumors (P<.001). Conversely, among 68 cases treated with cystectomy, significantly lower expression of GATA binding protein 3 was found in pN0 tumors (32/47 [68%]) than in node-positive tumors (20/21 [95%]) (P=.027). Kaplan-Meier and log-rank tests further revealed that overall positivity (P=.048) or strong positivity (P=.025) of GATA binding protein 3 correlated with progression of muscle-invasive tumors. Multivariate analysis identified high GATA binding protein 3 expression as a strong prognosticator for progression (P=.052) and cancer-specific survival (P=.040) of muscle-invasive tumors. Moreover, there were significant correlations between GATA binding protein 3 expression vs androgen receptor overexpression, estrogen receptor α overexpression, or loss of estrogen receptor ß expression. Thus, compared with benign urothelium, a significant decrease in the expression of GATA binding protein 3 in urothelial neoplasms was seen. Loss of GATA binding protein 3 was associated with high-grade and/or muscle-invasive tumors, whereas strong expression was an independent predictor of poor prognosis.

Regulation of human osteoclast development by dendritic cell-specific transmembrane protein (DC-STAMP).

Osteoclasts (OC) are bone-resorbing, multinucleated cells that are generated via fusion of OC precursors (OCP). The frequency of OCP is elevated in patients with erosive inflammatory arthritis and metabolic bone diseases. Although many cytokines and cell surface receptors are known to participate in osteoclastogenesis, the molecular mechanisms underlying the regulation of this cellular transformation are poorly understood. Herein, we focused our studies on the dendritic cell-specific transmembrane protein (DC-STAMP), a seven-pass transmembrane receptor-like protein known to be essential for cell-to-cell fusion during osteoclastogenesis. We identified an immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic tail of DC-STAMP, and developed an anti-DC-STAMP monoclonal antibody 1A2 that detected DC-STAMP expression on human tumor giant cells, blocked OC formation in vitro, and distinguished four patterns of human PBMC with a positive correlation to OC potential. In freshly isolated monocytes, DC-STAMP(high) cells produced a higher number of OC in culture than DC-STAMP(low) cells and the surface expression of DC-STAMP gradually declined during osteoclastogenesis. Importantly, we showed that DC-STAMP is phosphorylated on its tyrosine residues and physically interacts with SHP-1 and CD16, an SH2-domain-containing tyrosine phosphatase and an ITAM-associated protein, respectively. Taken together, these data show that DC-STAMP is a potential OCP biomarker in inflammatory arthritis. Moreover, in addition to its effect on cell fusion, DC-STAMP dynamically regulates cell signaling during osteoclastogenesis.

Combination of napsin A and TTF-1 immunohistochemistry helps in differentiating primary lung adenocarcinoma from metastatic carcinoma in the lung.

Differentiation of primary from metastatic adenocarcinoma in the lung can be challenging, and it demands sensitive and specific biomarkers, especially when the tissue for diagnosis is limited. Thyroid transcription factor-1 (TTF-1) has been considered a reliable marker for adenocarcinoma of lung origin. However, several recent studies have shown that TTF-1 immunostaining is also positive in adenocarcinomas arising in different organs including colon, endometrium, endocervix, and ovary. In addition, approximately 20% of lung primary adenocarcinomas are negative for TTF-1 immunostaining, and napsin A immunostaining has slightly higher sensitivity in detecting lung primary adenocarcinoma. We performed TTF-1 and napsin A immunostaining on 120 cases of primary lung adenocarcinomas and 37 cases of metastatic carcinomas in the lung. The results showed that 95 (79.2%) of 120 lung primary adenocarcinomas showed napsin A+/TTF-1+ double-positive immunostaining pattern. TTF-1⁻/napsin A+, TTF-1+/napsin A⁻, and TTF-1⁻/napsin A⁻ were seen in 8.3%, 3.3%, and 9.2% lung primary adenocarcinomas, respectively. Eight (21.6%) of the 37 metastatic carcinomas were positive for TTF-1 and they include clear-cell renal cell carcinomas completely negative for napsin A although napsin A was detected in 12 (80.0%) of 15 primary papillary and 3 (33.3%) of 9 primary clear-cell renal cell carcinomas. All renal epithelial neoplasms were TTF-1 negative. These findings indicate that double napsin A and TTF-1-positive immunostaining is highly specific for lung primary adenocarcinoma and the combination of these 2 biomarkers is warranted to help segregating primary lung adenocarcinoma from metastatic carcinoma in the lung.

High-grade neuroendocrine carcinomas of the lung highly express enhancer of zeste homolog 2, but carcinoids do not.

Enhancer of zeste homolog 2, the catalytic subunit of polycomb repressive complex 2, is a histone methyltransferase and plays an important role in cell proliferation and cell cycle regulation. It has been shown to be overexpressed in a number of malignant neoplasms. This study aimed to determine the expression pattern of enhancer of zeste homolog 2 in neuroendocrine tumors of the lung and the potential of enhancer of zeste homolog 2 to serve as a biomarker to segregate carcinoids from high-grade neuroendocrine carcinomas. Fifty-four cases, including 25 typical carcinoids, 7 atypical carcinoids, 9 large-cell neuroendocrine carcinomas, and 13 small-cell lung carcinomas, were immunohistochemically studied using a monoclonal antibody against enhancer of zeste homolog 2. All 13 small-cell lung carcinomas demonstrated moderate to strong nuclear staining with 12 exhibiting more than 90% of tumor cells staining. All 9 large-cell neuroendocrine carcinomas were moderately to strongly positive for enhancer of zeste homolog 2, with 6 cases having staining in more than 80% of tumor cells. In contrast, all 25 typical carcinoids and 6 atypical carcinoids showed only rare scattered enhancer of zeste homolog 2-positive tumor cells, with 1 case of atypical carcinoid exhibiting moderate staining in 40% of tumor cells. A subsequent validation study of the 14 specimens of lung or mediastinal lymph node biopsy and fine-needle aspiration, including 6 small-cell lung carcinomas, 2 large-cell neuroendocrine carcinomas, 5 typical carcinoids, and 1 atypical carcinoid, was performed. Enhancer of zeste homolog 2 was diffusely and strongly positive in all small-cell lung carcinomas and large-cell neuroendocrine carcinomas, even with severe crush artifact, whereas it was only positive in rare tumor cells in carcinoids. These findings support the formulation that enhancer of zeste homolog 2 may play an important role in the regulation of biologic behavior of high-grade neuroendocrine carcinomas and as a diagnostically useful marker in distinguishing high-grade neuroendocrine carcinomas from carcinoids.

Value of D2-40 in the differential diagnosis of pleural neoplasms with emphasis on its positivity in solitary fibrous tumor.

D2-40 is a new monoclonal antibody recognizing podoplanin and it is selective for lymphatic endothelium. Several studies have confirmed the reliability of D2-40 in the diagnosis of pleural malignant mesothelioma, but the evaluation of this antibody in other pleural neoplasms is limited. The aim of this study was to determine the diagnostic value of D2-40 in segregation of malignant mesothelioma from other pleural or lung neoplasms. Sixty-seven cases, including 36 pleural malignant mesotheliomas, 15 solitary fibrous tumors, 13 pleomorphic carcinomas, and 3 synovial sarcomas, were immunohistochemically studied using a D2-40 monoclonal antibody. Twenty-five (21 epithelioid and 4 biphasic) of 36 (69%) malignant mesotheliomas and 2 of 15 (13%) solitary fibrous tumors were positive for D2-40. The difference of D2-40 positivity between these 2 types of tumor was significant (P<0.001). No D2-40 positivity was detected in pleomorphic carcinomas (n=13) or synovial sarcomas (n=3). These findings showed that D2-40 was frequently positive in malignant mesothelioma, but could also be positive in a small portion of solitary fibrous tumor. These results indicate that D2-40 is a valuable marker for malignant mesothelioma, but caution should be taken when evaluating D2-40-positive pleural spindle cell neoplasms in limited small biopsy specimens, especially when the differential diagnosis includes solitary fibrous tumor and malignant mesothelioma.

Diagnostic utility of IMP3 in segregating metastatic melanoma from benign nevi in lymph nodes.

Depending on the Breslow depth of the primary melanoma, sentinel lymph node biopsy is considered as standard of care for the staging of cutaneous melanoma, and is one of the most important prognostic factors. The histologic analysis of these specimens becomes difficult to interpret when benign intranodal nevic cells mimic metastases. Insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP3), also known as K homology domain-containing protein overexpressed in cancer or L523S, is a member of the insulin-like growth factor-II mRNA-binding protein family and has been shown to have diagnostic utility in distinguishing cutaneous melanoma from benign nevi. In this study, 43 sentinel lymph node biopsy specimens, including 13 with benign intranodal nevi and 30 with metastatic melanoma (two cases containing both benign nevi and metastatic melanoma), from 41 patients were immunohistochemically analyzed with a monoclonal antibody against IMP3. None of the benign intranodal nevi expressed IMP3, whereas 21 out of 30 (70%) of the lymph nodes containing metastatic melanoma did. It seems that IMP3 is helpful in distinguishing benign intranodal nevi from metastatic melanoma in sentinel lymph node biopsy specimens, and could be a valuable diagnostic adjunct in sentinel lymph node biopsy assessment in which questions arise as to the malignancy of the melanocytes present.