Loralee McMahon

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.

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‐STAMPhigh cells produced a higher number of OC in culture than DC‐STAMPlow 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.

A lower Allred score for progesterone receptor is strongly associated with a higher recurrence score of 21-gene assay in breast cancer.

ABSTRACT Among the 77 infiltrating breast carcinomas, we found that progesterone receptor (PR) expression was inversely associated with recurrence score (RS, p < .0001). RS is also significantly associated with tubule formation, mitosis, and luminal B subtype. The equation of RS = 17.489 + 2.071 (tubal formation) + 2.926 (mitosis) –2.408 (PR) –1.061 (HER2) + 7.051 (luminal A) + 29.172 (luminal B) predicts RS with an R2 of 0.65. In conclusion, PR negativity, luminal B subtype, tubal formation, and mitosis are strongly correlated with a higher RS.

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 β 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.

Diagnostic utility of PAX8, TTF-1 and napsin A for discriminating metastatic carcinoma from primary adenocarcinoma of the lung.

Abstract TTF-1 and napsin A are useful biomarkers for differentiating primary lung adenocarcinoma from metastatic tumors. Studies have shown, however, that TTF-1 and napsin A also can be expressed in extrapulmonary carcinomas, and that a small fraction of primary lung adenocarcinomas do not co-express these two markers. We attempted to determine whether a tissue-specific transcriptional factor, PAX8, can help determine primary sites of lung carcinomas. Immunohistochemical stains for PAX8, TTF-1 and napsin A were performed on 103 cases of metastatic lung carcinomas from a variety of origins and 120 cases of primary lung adenocarcinomas. Our data demonstrated that all 103 metastatic carcinomas were negative for napsin A, while 14 (13.6%; four thyroid, two endometrium, three colon, one prostate, one salivary adenoid cystic, two renal cell carcinomas, and one ovary) showed weak to strong TTF-1 nuclear staining in 5–60% of the tumor cells. All primary lung adenocarcinomas were negative for PAX8, whereas 46 (44.7%) metastatic carcinomas from the kidney (29/33), ovary (6/8), endometrium (5/5), endocervix (1/1), thyroid (4/5) and urinary tract (1/3) were positive for PAX8. Our data demonstrate that of combined use of PAX8, TTF-1 and napsin A is reliable to separate reliably lung primary from metastatic tumors.

MACC1 is related to colorectal cancer initiation and early-stage invasive growth.

OBJECTIVES To investigate metastasis associated in colon cancer 1 (MACC1) and MET expression in colorectal adenoma, Tis, early-stage invasive (T1 and T2), and advanced adenocarcinoma with liver metastasis using immunohistochemistry. METHODS Ninety-three paraffin-embedded colorectal tumor specimens were immunohistochemically analyzed for MACC1 and MET protein expression. RESULTS MACC1 expression was upregulated in the transition from adenoma to Tis; its expression was further elevated during tumor progression from Tis to early invasive carcinoma. MET expression was constant from adenoma to Tis and to T1 but significantly increased as tumor progression to T2. Both MACC1 and MET expression were enhanced in advanced carcinoma with liver metastasis. CONCLUSIONS Stepwise elevation of MACC1 expression in key points of colorectal cancer development suggests that MACC1 may contribute to cancer initiation and early invasive growth. High expression of both MACC1 and MET may relate to distant metastasis.

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.

Loss of PLZF Expression in Prostate Cancer by Immunohistochemistry Correlates with Tumor Aggressiveness and Metastasis

PLZF is a transcription repressor, which plays a critical role in development, spermatogenesis and oncogenesis. Down-regulation of PLZF has been found in various tumor cell lines. There has been virtually no tissue study on the expression of PLZF in prostate cancer (PCa). PCa is a heterogeneous disease, most of which are indolent and non-lethal. Currently there are no biomarkers that distinguish indolent from aggressive PCa; therefore there is an urgent need for such markers to provide clinical decision support. This study aimed to investigate the expression of PLZF by immunohistochemistry in different grade as well as metastatic PCa and to correlate the alteration of PLZF expression with PCa aggressiveness. We studied a total of 83 primary PCa from biopsies, 43 metastatic PCa and 8 paired primary and metastatic PCa from radical prostatectomies with lymph node dissection. Our results demonstrated that PLZF was strongly expressed in almost all (~100%) benign luminal cells (n=77) and low grade (Gleason pattern 3) PCa (n=70) and weak or absent (100%) in basal cells (n=70). Decreased or lost expression of PLZF was evidenced in 26% of high-grade (Gleason 4 and 5) primary PCa (n=70) and 84% metastatic PCa (n=43). The primary high grade PCa in the prostatectomies shared similar PLZF loss/decrease and histomorphology to that of paired parallel lymph node metastases. These data demonstrated that down-regulation of PLZF is an important molecular process for tumor progression and loss of PLZF expression detected by routine immunohistochemistry is a promising and valuable biomarker for PCa aggressiveness and metastasis in the personalized care of PCa.

Expression of androgen receptor and its association with estrogen receptor and androgen receptor downstream proteins in normal/benign breast luminal epithelium.

The androgen receptor (AR) is strongly expressed in the majority of breast carcinomas, but its role in breast hormonal carcinogenesis is not clear. We believe a better knowledge of the biology of normal/benign breast tissue will be the key to understanding this process. Using standard immunohistochemical staining on consecutive sections and dual immunohistochemical labeling, we studied the expression pattern of AR and estrogen receptor (ER) in normal/benign breast luminal epithelial cells. We found that most of the AR-positive cells are also ER positive, about 10% of the cells are AR-positive only, whereas ER-positive only cells are uncommon, a distribution pattern of hormone receptor expression similar to what was revealed in invasive breast carcinomas. Whereas the expression of AR downstream proteins, such as prostate-specific antigen and gross cystic disease fluid protein, was either negative or unrelated to the AR status. We conclude that AR and ER expression status in invasive breast carcinomas reflects that of their progenitor cells in terminal duct lobular units. Our study did not reveal the expression of AR downstream proteins in normal/benign luminal epithelial cells at the regular immunohistochemistry level.

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.