Karen Dresser

Expression of α-methylacyl-coa racemase (p504s) in various malignant neoplasms and normal tissues: a study of 761 cases

α-methylacyl CoA racemase (AMACR), also known as P504S, plays an important role in peroxisomal beta-oxidation of branched-chain fatty acids. It has recently been shown that AMACR is highly expressed in prostate cancer and that it may be an important diagnostic marker for prostate carcinoma. However, little is known about expression of AMACR in normal tissues and other malignant tumors. In this study, we investigated expression of AMACR in 539 malignant tumors and 222 normal human tissues of various types by immunohistochemical analysis. mRNA levels of AMACR in normal organs and in selected tumors were assessed by real time PCR. In normal tissue, high expression of AMACR mRNA was identified in liver, kidney and salivary gland, while AMACR protein was detected in liver (hepatocytes), kidney (tubular epithelial cells), lung (only bronchial epithelial cells), and gallbladder (only mucosal epithelial cells). High expression of AMACR mRNA was found in prostate, liver, and kidney cancers but rarely in stomach and bladder cancers. A high percent of adenocarcinomas arising from these organs express AMACR, including 17 of 21 (81%) of hepatocellular carcinomas and 18 of 24 (75%) of renal cell carcinomas. In addition, carcinomas arising from tissues normally not expressing AMACR were also positive for the antigen, including 17 of 18 (94%) prostate carcinomas, 9 of 29 (31%) of urothelial carcinomas, and 4 of 15 (27%) of gastric adenocarcinomas. Two hundred and fifty cases of adenocarcinomas from lung, breast, pancreas, bile duct, adrenal gland, salivary gland, ovary, thyroid and endometrium were negative or rarely positive for AMACR. Neuroendocrine carcinomas rarely expressed AMACR. Melanomas, squamous cell carcinomas, basal cell carcinomas, soft tissue tumors (including epithelioid sarcomas and synovial sarcoma), thymomas, and germ cell tumors were negative for AMACR. Our data provide important baseline information for using AMACR in clinical practice and also are valuable in furthering understanding of the pathogenic role of AMACR in malignant neoplasms.

P504S/α-methylacyl-CoA racemase: A useful marker for diagnosis of small foci of prostatic carcinoma on needle biopsy

Establishing a definitive diagnosis of malignancy in prostate needle biopsies with very small foci of adenocarcinoma is a major diagnostic challenge for surgical pathologists. A positive diagnostic marker specific for prostatic adenocarcinoma may enhance our ability to detect limited prostate cancer and reduce errors in diagnosis. P504S, also known as &agr;-methylacyl-CoA racemase, recently identified by cDNA subtraction and microarray technology, might serve as such a specific marker because it has been demonstrated to be highly expressed in prostatic adenocarcinoma, but not in benign prostatic glands. However, whether small foci of carcinoma can be reliably detected by this marker is a crucial question for its clinical application. The aim of this study was to assess the utility of P504S immunohistochemistry in detecting small amounts of prostate cancer in prostate needle biopsies. A total of 142 prostate needle biopsies, including 73 cases with a small focus of prostatic adenocarcinoma (≤1 mm) and 69 benign prostates, were examined by using immunohistochemistry for P504S and high molecular weight cytokeratin (34&bgr;E12). P504S immunoreactivity was found in 69 of 73 cases (94.5%) of carcinoma but not in any benign prostates (0 of 69) or benign glands adjacent to malignant glands. The 34&bgr;E12 immunostaining confirmed the absence of basal cells in the focus of carcinoma in all 73 cases. The high specificity and sensitivity of P504S in the detection of minimal prostatic adenocarcinoma indicated its potential diagnostic value in clinical practice. Using a combination of P504S and 34&bgr;E12 can help the diagnosis of limited prostatic adenocarcinoma on needle biopsy.

KOC (K homology domain containing protein overexpressed in cancer): a novel molecular marker that distinguishes between benign and malignant lesions of the pancreas.

KOC (K homology domain containing protein overexpressed in cancer) is a novel oncofetal RNA-binding protein highly expressed in pancreatic carcinomas. Recently, Corixa Corporation developed a monoclonal antibody specific for KOC that can be used with standard immunohistochemical techniques. The purposes of this study were 1) to assess KOC mRNA expression in pancreatic carcinoma, 2) to determine the pattern of KOC immunoexpression among benign, borderline, and malignant pancreatic epithelial lesions, and 3) to evaluate the utility of the KOC antibody in distinguishing between these entities. mRNA was isolated from fresh pancreatic tissues (19 carcinomas, 2 normal pancreas, 1 chronic pancreatitis) and amplified using standard RT-PCR techniques. Fifteen of 19 (79%) carcinomas overexpressed KOC mRNA relative to non-neoplastic tissue samples and expression increased progressively with tumor stage: the mean copy number of KOC mRNA transcripts was 1.5, 11.1, 31, and 28 for stage I, II, III, and IV carcinomas, respectively, compared with 0.9 and 1 for normal pancreatic tissue and chronic pancreatitis, respectively. Immunostains using the KOC antibody were performed on 50 surgical resection specimens (38 invasive adenocarcinomas, 3 intraductal papillary-mucinous neoplasms, 2 mucinous cystic neoplasms, 7 chronic pancreatitis). KOC staining was present in 37 of 38 (97%) carcinomas: the staining reaction was moderate or strong in 36 of 38 (94%) and present in >50% of the tumor cells in 35 of 38 (92%) cases. Severe dysplasia of the ductal epithelium, present in 19 foci of intraductal papillary mucinous carcinoma, mucinous cystadenocarcinoma, and grade 3 pancreatic intraepithelial neoplasia (PanIN3) showed strong or moderate staining in 15 (79%) cases, whereas foci of mild and moderate dysplasia (intraductal papillary-mucinous neoplasms and mucinous cystic neoplasms with adenoma and/or moderate dysplasia, PanIN1, and PanIN2) were uniformly negative for this marker in 25 and 22 cases, respectively. In the normal pancreas, weak background staining of acini was present in 12 of 50 (24%) cases but was easily distinguishable from the type of staining identified in neoplastic epithelium, and benign ducts and ductules were negative in all cases. Four of 38 (11%) foci of chronic pancreatitis, present in the 7 resections performed for chronic pancreatitis as well as 31 foci of peritumoral chronic pancreatitis, showed weak staining in <10% of the ductules. We conclude that KOC is a sensitive and specific marker for carcinomas and high-grade dysplastic lesions of the pancreatic ductal epithelium. Therefore, immunostains directed against KOC may be of diagnostic utility in the evaluation of pancreatic lesions, particularly when biopsy material is limited.

Expression of α-methylacyl-CoA racemase (P504S) in atypical adenomatous hyperplasia of the prostate

Atypical adenomatous hyperplasia (AAH) of the prostate, also known as adenosis, is characterized by a proliferation of prostatic glands with abnormal architectural patterns, but without significant cytologic atypia. In some cases it may be difficult to distinguish AAH from prostatic carcinoma. Additionally, it is not clear whether AAH is a precursor lesion of prostatic adenocarcinoma. P504S, a protein highly expressed in prostatic adenocarcinoma, has been recently shown to be a marker of prostate cancer. The goal of this study is to examine the expression of P504S in AAH by immunohistochemistry. A total of 80 prostate specimens, including 40 cases of AAH (prostatectomy N = 30, biopsy N = 6, transurethral resection N = 4), 20 cases of prostatic adenocarcinomas, and 20 cases of benign prostatic hyperplasia, were studied. Immunohistochemistry for a prostate cancer marker &agr;-methylacyl-CoA racemase (P504S) and a basal cell-specific marker 34&bgr;E12 was performed in all the cases. The 34&bgr;E12 stain confirmed the presence of patchy basal cells in all 40 cases of AAH. P504S was undetectable in the majority of AAHs (33 of 40, 82.5%), focally expressed in four of 40 (10.0%), or diffusely positive only in three of 40 (7.5%) cases of AAH. Interestingly, two of seven P504S-positive AAHs were found adjacent to adenocarcinoma. In contrast, all benign prostatic hyperplasias (20 of 20, 100%) were negative for P504S, and all 20 cases of prostatic carcinomas (100%) showed a diffuse P504S staining pattern. These findings suggest that AAH is a heterogenous entity. The biologic significance of P504S expression in a small subset of AAH remains to be determined. Because most cases of AAH are negative for P504S, immunostaining of P504S is also of diagnostic value in distinguishing the majority of AAHs from prostatic adenocarcinoma.

CXCL10 Is Critical for the Progression and Maintenance of Depigmentation in a Mouse Model of Vitiligo

Neutralizing CXCL10 reverses established vitiligo. New Skin in the Game of Vitiligo Therapy The immune system is tasked with protecting the body from invading pathogens. Yet, sometimes, immune cells themselves attack the tissues they are supposed to protect. One such autoimmune disease is vitiligo, where immune cells are thought to attack melanocytes—the pigment-producing cells in the skin. Individuals with vitiligo have depigmented areas in their skin, which is disfiguring and also increases the risk of skin damage. Now, Rashighi et al. suggest that blocking the chemokine CXCL10 may restore pigmentation in patients with vitiligo. The authors examined gene expression in lesional skin from vitiligo patients and found an interferon-γ–specific signature, including differential expression of the chemokine CXCL10. They found that CXCL10 was up-regulated in vitiligo patients; its receptor CXCR3 was up-regulated in T cells from these patients as well. The authors then looked in a mouse model of vitiligo to determine the functional relevance of this observation. Mice with CXCR3-deficient T cells developed a much less severe form of vitiligo, as did mice lacking CXCL10 or treated with a CXCL10-neutralizing antibody. What’s more, this CXCL10-neutralizing antibody resulted in repigmentation in mice with already established vitiligo lesions. These data suggest that CXCL10 neutralization should be considered as a potential treatment for vitiligo. Vitiligo is an autoimmune disease of the skin that results in disfiguring white spots. There are no U.S. Food and Drug Administration–approved treatments for vitiligo, and most off-label treatments yield unsatisfactory results. Vitiligo patients have increased numbers of autoreactive, melanocyte-specific CD8+ T cells in the skin and blood, which are directly responsible for melanocyte destruction. We report that gene expression in lesional skin from vitiligo patients revealed an interferon-γ (IFN-γ)–specific signature, including the chemokine CXCL10. CXCL10 was elevated in both vitiligo patient skin and serum, and CXCR3, its receptor, was expressed on pathogenic T cells. To address the function of CXCL10 in vitiligo, we used a mouse model of disease that also exhibited an IFN-γ–specific gene signature, expression of CXCL10 in the skin, and up-regulation of CXCR3 on antigen-specific T cells. Mice that received Cxcr3−/− T cells developed minimal depigmentation, as did mice lacking Cxcl10 or treated with CXCL10-neutralizing antibody. CXCL9 promoted autoreactive T cell global recruitment to the skin but not effector function, whereas CXCL10 was required for effector function and localization within the skin. Surprisingly, CXCL10 neutralization in mice with established, widespread depigmentation induces reversal of disease, evidenced by repigmentation. These data identify a critical role for CXCL10 in both the progression and maintenance of vitiligo and thereby support inhibiting CXCL10 as a targeted treatment strategy.

IMP3 is a novel biomarker for adenocarcinoma in situ of the uterine cervix: an immunohistochemical study in comparison with p16 INK4a expression

Adenocarcinoma in situ of the uterine cervix remains a diagnostic challenge in a small proportion of cases. This suggests a need for biomarker that may be of help in establishing the diagnosis. The aim of this study was to evaluate the potential of insulin-like growth factor-II mRNA-binding protein 3 and cyclin-dependent kinase inhibitor p16INK4a as biomarkers for adenocarcinoma in situ. Forty-four samples of adenocarcinoma in situ from 40 patients and 23 control cases of benign uterine cervix were included in this study. In addition to benign endocervical epithelium, 19 of these 23 control cases also showed focal tubal metaplasia. Cytoplasmic immunoreactivity for insulin-like growth factor-II mRNA-binding protein 3 was identified in 41 (93%) adenocarcinoma in situ samples, among which, 29 (71%), 10 (24%), and 2 (5%) samples showed insulin-like growth factor-II mRNA-binding protein 3 positive staining in 50% or more, >5 to <50 and <5% of adenocarcinoma in situ lesional cells, respectively. Immunohistochemical reaction intensity for insulin-like growth factor-II mRNA-binding protein 3 was found to be strong in 34 adenocarcinoma in situ samples, intermediate in five, and weak in two. All 23 control cases were negative for insulin-like growth factor-II mRNA-binding protein 3. p16INK4a expression was identified in all of the adenocarcinoma in situ samples with intermediate staining intensity seen in seven samples and strong in the remainder. Fourteen of 19 (74%) tubal metaplasia cases showed p16INK4a immunoreactivity in >50% of the tubal metaplastic epithelium with staining intensity ranging from weak to strong. Our findings demonstrate significant expression of insulin-like growth factor-II mRNA-binding protein 3 and p16INK4a in adenocarcinoma in situ as compared to benign endocervical glands, suggesting that expression of these biomarkers may be helpful in the distinction of adenocarcinoma in situ from benign endocervical glands, particularly in difficult borderline cases.

Using an AMACR (P504S)/34βE12/p63 Cocktail for the Detection of Small Focal Prostate Carcinoma in Needle Biopsy Specimens

We assessed the usefulness of immunohistochemical analysis with a 3-antibody cocktail (alpha-methylacyl coenzyme A racemase [AMACR, or P504S], 34betaE12, p63) and a double-chromogen reaction for detection of limited prostate cancer in 138 needle biopsy specimens, including 82 with small foci of prostatic adenocarcinoma and 56 benign prostates. When carcinoma was present, red cytoplasmic granular staining (AMACR) in the malignant glands and cells and dark brown nuclear (p63) and cytoplasmic (34betaE12) staining in basal cells of adjacent nonmalignant glands were found. Of 82 cases of small foci of prostatic adenocarcinoma, 78 (95%) expressed AMACR; all malignant glands were negative for basal cell staining. All benign glands adjacent to malignant glands were recognized easily by basal cell marker positivity and little or no AMACR expression. No benign glands were simultaneously positive for AMACR and negative for basal cell markers (specificity, 100%). There were no differences in intensity and numbers of positive glands with double-chromogen staining compared with using 1-color staining. Our results indicate that immunohistochemistry with a 3-antibody cocktail and double chromogen is a simple and easy assay that can be used as a routine test, which overcomes the problems of studying small lesions in prostate needle biopsies with multiple immunohistochemical stains.

Sp1, a New Biomarker That Identifies a Subset of Aggressive Pancreatic Ductal Adenocarcinoma

Pancreatic adenocarcinoma is one of the leading causes of cancer-related deaths in the United States. Sp1 is a sequence-specific DNA binding protein that is important in the transcription of a number of regulatory genes involved in cancer cell growth, differentiation, and metastasis. In this study, we investigated Sp1 expression in pancreatic ductal adenocarcinoma and its association with clinical outcome. We studied 42 patients with primary pancreatic adenocarcinoma. The expression of Sp1 in pancreatic adenocarcinoma was evaluated by immunohistochemical staining. All 42 patients had clinical follow-up information and were evaluated for survival. Sp1 protein was aberrantly overexpressed in a subset of primary pancreatic adenocarcinoma. These tumors all developed metastasis, whereas none of the primary tumors without lymph node metastasis showed Sp1 overexpression. Statistically, Sp1 overexpression was associated with higher stage, higher grade, and lymph node metastasis (P < 0.001, P = 0.036, and P < 0.0001, respectively). Additionally, patients of this subset had a much shorter overall survival than patients without Sp1 overexpression, as evidenced by Kaplan-Meier plots and the log-rank test (P = 0.002). The 5-year overall survival rate was 19% in patients with Sp1 overexpression, compared with 55% in patients without Sp1 overexpression. The median survival was only 13 months for patients with Sp1 overexpression, compared with 65 months for patients without Sp1 overexpression. In conclusion, Sp1 is a new biomarker that identifies a subset of pancreatic ductal adenocarcinoma with aggressive clinical behavior. It can be used at initial diagnosis of pancreatic adenocarcinoma to identify patients with an increased probability of cancer metastasis and much shortened overall survival. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1648–52)

IMP3 predicts aggressive superficial urothelial carcinoma of the bladder

Purpose: In this study, we investigated whether an oncofetal protein, IMP3, can serve as a new biomarker to predict progression and metastasis of early-stage urothelial carcinoma of the bladder. Experimental Design: The expression of IMP3 in 242 patients with primary superficial bladder urothelial carcinoma and metastatic urothelial carcinoma was evaluated by immunohistochemistry. Patients with primary superficial urothelial carcinoma of the bladder were further investigated by use of survival analysis. Results: Twenty percent (42 of 214) of primary superficial urothelial carcinomas and 93% (26 of 28) of metastatic urothelial carcinomas expressed IMP3. Kaplan-Meier plots and log-rank tests showed that patients with IMP3-positive tumors had a much lower progression-free survival (P = 0.0002) and disease-free survival rate (P = 0.0067) than did those with IMP3-negative tumors. The 5-year progression-free and disease-free survival rates were 91% and 94% in IMP3-negative patients versus 64% and 76% in IMP3-positive patients, respectively. Sixty percent of IMP3-positive patients with superficial invasive urothelial carcinoma at initial diagnosis went on to develop metastases, whereas no metastasis was found in IMP3-negative patients (P = 0.0017). In the multivariable Cox analysis, patients with IMP3 expression in their superficial urothelial carcinomas subsequently developed invasive tumors or metastasis at a rate that was about five times greater than cases without expression of IMP3 adjusting for other well-known clinical variables (tumor stage and grade, etc.). Conclusions: Our findings indicate that IMP3 is an independent prognostic marker that can identify a group of patients with a high potential to develop progression and who might benefit from early aggressive therapy.

Microcystic adnexal carcinoma : an immunohistochemical reappraisal

Even though immunohistochemical comparisons of microcystic adnexal carcinoma vs infiltrative basal cell carcinoma and desmoplastic trichoepithelioma exist, they are mostly restricted to the use of a single stain. In addition, a comparison with squamous cell carcinoma has not been reported previously. In this study, we compare the expression of cytokeratin (CK) 15, CK7, CK20, CK903, carcinoembryonic antigen (CEA), CD10, CD15 and BerEP4 in 13 microcystic adnexal carcinoma, eight desmoplastic trichoepithelioma, 10 infiltrative basal cell carcinoma, and eight squamous cell carcinoma of which five exhibited ductal differentiation. We found that the majority of microcystic adnexal carcinoma (92%) and desmoplastic trichoepithelioma (100%) cases expressed CK15 while the infiltrative basal cell carcinoma and squamous cell carcinoma cases were all negative. Forty percent of infiltrative basal cell carcinoma expressed CK7; while only two microcystic adnexal carcinoma cases (15%) and one squamous cell carcinoma with ductal differentiation (12%) expressed CK7 in the remaining three tumor categories. None of the desmoplastic trichoepithelioma expressed CK7. All tumors were strongly positive for CK903. While the neoplastic cells were negative, luminal staining of ductal structures was noted for CK7, CD15 and CEA in some of the microcystic adnexal carcinoma, desmoplastic trichoepithelioma and squamous cell carcinoma with ductal differentiation cases. Sixty percent of infiltrative basal cell carcinoma, 31% of microcystic adnexal carcinoma, and 25% of squamous cell carcinoma express CD10. BerEP4 expression was noted in 38% of microcystic adnexal carcinoma, 57% of desmoplastic trichoepithelioma, 100% of infiltrative basal cell carcinoma, and 38% of squamous cell carcinoma. In conclusion, we found CK15 to be a useful marker in distinguishing microcystic adnexal carcinoma from infiltrative basal cell carcinoma and squamous cell carcinoma with ductal differentiation. Our experience indicates that microcystic adnexal carcinoma and desmoplastic trichoepithelioma have a similar immunohistochemical profile that is, CK15+ and BerEP4+/−; thus, additional studies are needed to separate these two entities.