ALDH7A1 expression is associated with recurrence in patients with surgically resected non-small-cell lung carcinoma.

AIM: The purpose of this study was to describe the prognostic significance of ALDH7A1 in surgically treated non-small-cell lung carcinoma. (NSCLC). MATERIALS & METHODS: We immunohistochemically analyzed ALDH7A1 expression in surgically resected NSCLC from 89 patients using a tissue microarray. RESULTS: ALDH7A1 staining was positive in 43 patients and negative in 44 patients, with two tumor sections missing. For stage I NSCLC patients, ALDH7A1 positivity was associated with decreased recurrence-free and overall survival. Multivariate analysis demonstrated that ALDH7A1-expressing NSCLC tumors had a significantly higher incidence of lung cancer recurrence compared with patients with ALDH7A1-negative tumors, although there was no association with overall survival. CONCLUSION: For patients with NSCLC, low ALDH7A1 expression was associated with a decreased incidence of cancer recurrence. Specifically in stage I patients, negative staining for ALDH7A1 was associated with improved recurrence-free and overall survival, suggesting a predictive role in surgically treated patients.

Lung cancer diagnosis from proteomic analysis of preinvasive lesions.

Early detection may help improve survival from lung cancer. In this study, our goal was to derive and validate a signature from the proteomic analysis of bronchial lesions that could predict the diagnosis of lung cancer. Using previously published studies of bronchial tissues, we selected a signature of nine matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) mass-to-charge ratio features to build a prediction model diagnostic of lung cancer. The model was based on MALDI MS signal intensity (MALDI score) from bronchial tissue specimens from our 2005 published cohort of 51 patients. The performance of the prediction model in identifying lung cancer was tested in an independent cohort of bronchial specimens from 60 patients. The probability of having lung cancer based on the proteomic analysis of the bronchial specimens was characterized by an area under the receiver operating characteristic curve of 0.77 (95% CI 0.66-0.88) in this validation cohort. Eight of the nine features were identified and validated by Western blotting and immunohistochemistry. These results show that proteomic analysis of endobronchial lesions may facilitate the diagnosis of lung cancer and the monitoring of high-risk individuals for lung cancer in surveillance and chemoprevention trials.

The phosphatidylinositol 3' kinase-Akt-mammalian target of rapamycin pathway in smooth muscle tumors of the uterus: selected protein expression patterns and their clinicopathologic implications.

Preclinical analyses strongly implicate the phosphatidylinositol 3' kinase-Akt-mammalian target of the rapamycin (P13K-Akt-mTOR) signaling pathway in smooth muscle tumorigenesis and differentiation, indicating that this pathway may be a suitable molecular target for the development of anticancer chemotherapeutic agents. The purpose of this study is to define the frequency and patterns of expression of 3 proteins in this pathway (mTOR, Akt, and PI3-K) in smooth muscle tumors of the uterine corpus, and to establish whether the expression of any of these proteins has independent prognostic significance. The expression patterns of mTOR, pan-Akt, and PI3-K were evaluated by immunohistochemistry in 31 uterine leiomyosarcomas and 10 leiomyomata, and the results were correlated with clinicopathologic parameters. Cases were scored by multiplication of staining intensity (on a 0 to 3+scale) and the extent/distribution of immunoreactivity (on a 0 to 4+ scale) for potential scores that ranged from 0 to a maximum of 12. Cases with scores of 4+to 12+(moderate, 4+ to 8+; high, 9+ to 12+ immunoreactivity) were considered positive. Associated peritumoral normal myometrium was present in 27 cases. All 31 leiomyosarcomas were pan-Akt positive, with 80.6% of the positive cases displaying high scores, whereas all 10 leiomyomata and 27 normal myometria were entirely pan-Akt negative. High pan-Akt scores were associated with high tumor grade but not with advanced stage or outcome. Every tumoral and nontumoral sample that was evaluated showed immunoreactivity for mTOR. PI3-K was positive in 20 (64.5%) of the 31 leiomyosarcomas but in none of the leiomyomata. High scores of PI3-K were associated with late pathologic stage (P=0.0022). High PI3-K scores, high pan-Akt scores, and PI3-K positivity were not independently associated with reduced disease-specific survival on multivariate analysis. Our findings suggest that relative to the normal myometrium, there is indeed dysregulation of the P13K-Akt-mTOR pathway in uterine smooth muscle tumors and especially in uterine leiomyosarcomas. Pan-Akt, mTOR, and PI3-K expression lacked independent prognostic significance in this pilot study, but additional and larger analyses are required. If corroborated in other laboratories, the expression patterns of proteins in this pathway, especially pan-Akt, may be of diagnostic use.

IgG4 plasma cells in inflammatory myofibroblastic tumor: inflammatory marker or pathogenic link?

Inflammatory myofibroblastic tumor is a rare mesenchymal neoplasm that harbors an anaplastic lymphoma kinase (ALK) gene rearrangement in the majority of cases. It is composed of fibroblastic-myofibroblastic cells with a characteristic inflammatory infiltrate that consists predominantly of plasma cells. In contrast, IgG4-related sclerosing disease is a recently described multisystem disorder with a histological appearance similar to inflammatory myofibroblastic tumor. The plasma cell infiltrate is characteristic in IgG4-related sclerosing disease and has been studied as a tool to render this diagnosis. Histologically, the two disorders overlap, although there are significant clinical differences. This study analyzes the histological appearance of 36 inflammatory myofibroblastic tumors, compares them with IgG4-related sclerosing disease, and assesses the plasma cell profile using immunohistochemistry to determine the range and proportion of IgG4 plasma cells. The majority of patients were children and young adults, mainly with solitary masses and no clinical manifestations of IgG4-related sclerosing disease. ALK-1 positivity was present in 23 cases (64%). None showed obliterative phlebitis or prominent lymphoid aggregates. Of 36 inflammatory myofibroblastic tumors, 15 cases showed an IgG4/IgG ratio ≥0.10, a cutoff described in the literature as supportive of IgG4-related sclerosing disease and up to 33 IgG4-positive plasma cells per high-power field indicating a mild-to-moderate increase as compared with IgG4-related sclerosing disease. Currently, the diagnostic recognition of inflammatory myofibroblastic tumor is based on clinicopathological features and diagnostic adjuncts, such as ALK-1 reactivity and genetic tests. Although inflammatory myofibroblastic tumor and IgG4-related sclerosing disease are distinct entities, a subset of inflammatory myofibroblastic tumors exhibit an IgG4/IgG ratio that is within the range for IgG4-related sclerosing disease. Therefore, the ratio alone cannot be used as a reliable discriminator between these two entities and other clinical and pathologic features must always be taken into account.

Markers of epithelial-mesenchymal transition and epithelial differentiation in sarcomatoid carcinoma: utility in the differential diagnosis with sarcoma.

The distinction between sarcomatoid carcinoma (SC) and bona fide sarcoma can be difficult using conventional immunohistochemical markers. Epithelial-mesenchymal transition (EMT) has been proposed as a histogenetic mechanism for the development of SC. Expression of selected markers of EMT (Twist and Slug) was compared with other markers of epithelial differentiation in SC and spindle cell sarcoma to determine the utility of these antigens in this differential diagnosis. Twenty-seven cases of SC (excluding those of gynecologic origin) were stained by immunohistochemistry for cytokeratins (AE1/AE3, 5D3, CK5/6, and 34betaE12), p63, claudin-1, claudin-7, epithelial cadherin, placental cadherin, epithelial cell adhesion molecule/epithelial-specific antigen, 14-3-3sigma, Twist, and Slug. A comparison group of 21 spindle or pleomorphic spindle cell sarcomas was also studied. Immunohistochemical stains were scored in a semiquantitative manner and subsequent exploratory analyses were performed using logistic regression and chi2 tests. Only cytokeratin AE1/AE3 specifically labeled SC in a statistically significant manner. Other epithelial-specific markers tested did not distinguish SC from sarcoma primarily owing to low sensitivity. However, when positive, immunostains such as CK5/6, membranous epithelial cadherin, and nuclear p63 may aid in the distinction of SC from sarcoma. EMT markers were expressed in most cases of both SC and sarcoma, and were not useful in making a differential diagnosis between these neoplasms.

Cytoplasmic clusterin expression is associated with longer survival in patients with resected non small cell lung cancer.

BACKGROUND: Clusterin is a glycoprotein that has been implicated in many processes, including apoptosis, cell cycle regulation, and DNA repair. Previous studies have examined the prognostic value of clusterin expression in various malignancies. In the present study, we examined clusterin staining in tumors resected from patients with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Tumor specimens were obtained for 113 patients with completely resected NSCLC from paraffin-embedded tissue microarrays and stained with an antibody specific for clusterin. Staining patterns were observed and graded based on intensity and then correlated with clinical data. RESULTS: Positive cytoplasmic clusterin staining was observed in 44 patients, and weak/negative staining was observed in 62 patients. Patients who had tumors that stained positive for cytoplasmic clusterin had significantly longer survival in multivariate analysis (hazard ratio 0.487, 95% confidence interval 0.27-0.89). A correlation was also observed for recurrence-free survival, which approached statistical significance (hazard ratio 0.345, 95% confidence interval 0.12-1.02). In univariate analysis, patients with clusterin-positive tumors had a 63% 3-year survival, whereas patients with clusterin-negative tumors had a 42% 3-year survival (P = 0.0108); clusterin-positive tumors also had significantly less recurrence (P = 0.0231). CONCLUSIONS: Cytoplasmic clusterin staining is present in a substantial number of NSCLC tumors and may be a biomarker for longer survival in patients with surgically resected NSCLC.

Steroid hormone receptor and COX-2 expression in chordoma.

Reports of sex steroid receptor expression in chordoma suggest that these tumors may be responsive to hormone manipulation therapy. Immunohistochemical stains for estrogen receptor (ER)-alpha, ER-beta, progesterone receptor (PR), androgen receptor (AR), and cyclooxygenase 2 (COX-2), were performed on a tissue microarray containing 21 samples of chordoma. Most chordomas expressed COX-2, ER-beta, and AR, whereas ER-alpha and PR stains were negative in all cases. ER-beta expression did not correlate with AR expression (P = .4142; McNemar test). There were no statistically significant correlations between the expression of any of these markers and anatomic location of tumor, patient sex, patient age, or disease-free survival. Chordomas commonly express COX-2, AR, and ER-beta. These findings may have therapeutic implications concerning the use of agents that inhibit or modulate these signaling molecules.

PDGFR-beta expression in small cell lung cancer patients.

BACKGROUND: Platelet derived growth factor (PDGF) and PDGFR-beta are expressed and have been found to have prognostic value in several human cancers. Data in non-small-cell cancer cell lines have suggested that PDGFR is a therapeutic target for drug development. In the current study PDGFR-beta expression and prognostic value in small cell lung cancer (SCLC) was investigated. METHODS AND MATERIALS: Paraffin-embedded tissue blocks from 53 patients with limited and extensive stage SCLC were obtained for immunohistochemical staining. Tumors from each patient were sampled 3 times and stained with PDGFR-beta specific antibody. Patients were divided into low and high staining groups based on intensity. RESULTS: There was high intensity PDGFR-beta staining in 20 patients with SCLC. Another 29 expressed low intensity PDGFR-beta staining, with only 4 patients showing no PDGFR-beta staining. There was no statistically significant difference in 5 year overall survival between patients with low levels of PDGFR-beta staining vs. those with high level staining SCLC tumors (p = 0.538). CONCLUSIONS: The present study found that the majority of SCLC patients express, at least, a low level of PDGF-beta. However, the level of PDGFR-beta expression was not a statistically significant predictor of 5 year overall survival in SCLC.

Expression of ABCA3 in developing lung and other tissues.

ABCA3 is a member of the ATP-binding cassette (ABC) family of transport proteins and is required for perinatal respiratory adaptation. Monoclonal and polyclonal antibodies were generated against a recombinant human ABCA3 peptide and used to assess its expression in the developing lung and adult tissues. Immunostaining for ABCA3 was detected at highest levels in type II epithelial cells of the lung but was also noted in other organs including liver, stomach, kidney, adrenal, pancreas, trachea, and brain. In the fetal lung, ABCA3 staining and mRNA increased prior to birth. Like other surfactant protein genes, ABCA3 expression was induced by thyroid transcription factor-1 in vitro. ABCA3 was coexpressed with SP-B and proSP-C in type II epithelial cells. ABCA3 staining was detected surrounding large, intracellular organelles consistent with its association with lamellar bodies. In the human fetal lung, ABCA3 staining was not detected prior to 22-23 weeks of gestation, except in the presence of pulmonary inflammation. ABCA3 was detected in type II epithelial cells of the human lung from 28 weeks of gestation and thereafter. Postnatally, intense ABCA3 staining was observed in hyperplastic epithelial cells relining injured airways in infants with chronic lung disease. Localization and regulation of ABCA3 in the respiratory epithelium is consistent with its proposed role in surfactant homeostasis. The role of ABCA3 in extrapulmonary tissues and organs remains to be elucidated. This manuscript contains online supplemental material at (www.jhc.org). Please visit this article online to view these materials.

Differential immune responses and pulmonary pathophysiology are induced by two different strains of respiratory syncytial virus.

In this study we performed comparisons of pulmonary responses between two different respiratory syncytial virus (RSV) antigenic subgroup A strains, A2 and Line 19. Line 19 strain induced significant dose-responsive airway hyperreactivity (AHR) in BALB/c mice at days 6 and 9 after infection, whereas the A2 strain induced no AHR at any dose. Histological examination indicated that A2 induced no goblet cell hyper/metaplasia, whereas the Line 19 induced goblet cell expansion and significant increases in gob5 and MUC5AC mRNA and protein levels in vivo. When examining cytokine responses, A2 strain induced significant interleukin (IL)-10 expression, whereas Line 19 strain induced significant IL-13 expression. When IL-13-/- mice were infected with Line 19 RSV, the AHR responses were abrogated along with gob5 gene expression. There was little difference in viral titer throughout the infection between the line 19- and A2-infected mice. However, the A2 strain grew to significantly higher titers than the Line 19 strain in HEp-2 cells in vitro. Thus, RSV Line 19-induced airway dysfunction does not correlate with viral load in vivo. These data demonstrate that different RSV strains of the same antigenic subgroup can elicit differential immune responses that impact the phenotypic expression of RSV-induced illness.

Nuclear survivin predicts recurrence and poor survival in patients with resected nonsmall cell lung carcinoma.

BACKGROUND: Survivin, which is a member of the inhibitor of apoptosis protein gene family, regulates both programmed cell death and mitosis. It has been shown that survivin expression and its subcellular localization both have prognostic value for patients with malignant disease. In this study, the authors investigated whether nuclear or cytoplasmic staining of survivin was a prognostic marker for patients with lung carcinoma. METHODS: Paraffin-embedded tissue blocks from 144 patients with Stage I and II resected nonsmall cell lung carcinoma (NSCLC) were obtained for immunohistochemical staining. Three specimens from each patient were prepared and stained with a survivin-specific antibody. Nuclear and cytoplasmic staining was graded from 1 to 3 based on intensity. RESULTS: Patients who had nuclear staining for survivin had a significantly increased risk of disease recurrence (hazard ratio, 2.95; P = 0.0046) and death (hazard ratio, 2.74; P = 0.0086). CONCLUSIONS: The nuclear presence of survivin may be an independent biomarker for disease recurrence and overall survival in patients with resected Stage I and II NSCLC.

Breast cancer risk associated with estrogen receptor expression in epithelial hyperplasia lacking atypia and adjacent lobular units.

Estrogen is associated with many epidemiologic risk factors for invasive breast cancer. Cells that express estrogen receptors (ERs) in epithelial hyperplasia lacking atypia (EHLA) may influence breast cancer progression. We conducted a nested case-control study of 268 women with biopsy-confirmed EHLA to determine whether immunohistochemical expression of ERalpha in EHLA affects subsequent breast cancer risk. Study subjects could not have a prior or current history of breast cancer or atypical hyperplasia. Immunohistochemical stains in individual lesions and adjacent normal lobules were considered positive if >or= 10% of epithelial cells stained for ERalpha. The risk of invasive breast cancer in EHLA patients with ERalpha-positive normal lobules was twice that of other EHLA patients (95% CI = 1.0-3.8). This risk was not affected by the ERalpha status of EHLA lesions. ERalpha expression in adjacent normal lobules increases the moderate breast cancer risk previously associated with EHLA.

Immunohistochemical expression of estrogen receptor in enlarged lobular units with columnar alteration in benign breast biopsies: a nested case-control study.

The prognostic and therapeutic implications of estrogen receptor (ER) status in breast cancer are well known. Whether ER status plays a role in benign breast lesions and the progression to malignancy has not been proven. Enlarged lobular units with columnar alteration (ELUCA), also known as unfolded lobular units, have been associated with mild elevations in subsequent breast cancer risk. We examined the association of ERalpha expression in ELUCA with invasive breast cancer risk. A nested case-control study was performed of women with ELUCA who had undergone benign breast surgery. Eighty-two women who developed invasive breast cancer on follow-up were matched by age and year of biopsy with 166 women who did not develop invasive breast cancer. Entry biopsies were stained for ERalpha (clone 6F11) without knowledge of subsequent cancer outcome. ELUCA lesions were scored as positive if greater than 10% of epithelial nuclei stained with ERalpha and at least one ELUCA contained >50% of cells staining for ERalpha. Relative risks of breast cancer were estimated by odds ratios derived from conditional logistic regression analyses. Thirty-nine percent of cases and 56% of controls had positive ERalpha staining in ELUCA. The relative risk of invasive breast cancer in women with ERalpha-negative ELUCA was 1.85 times that of women with ERalpha-positive lesions (95% confidence interval, 1.0-3.4, P=0.04). The presence of ERalpha staining in women with ELUCA is associated with a lower risk of developing subsequent invasive carcinoma. These findings have implications for risk assessment in benign breast biopsies and are of particular interest given the controversy currently surrounding hormone replacement therapy.

15-Lipoxygenase-2 expression in benign and neoplastic lung: an immunohistochemical study and correlation with tumor grade and proliferation.

15-Lipoxygenase-2 (15-LOX-2) is an arachidonic acid-metabolizing enzyme expressed in prostate, lung, skin, esophagus, and cornea. In the benign prostate, it is expressed in differentiated secretory epithelial cells, where its enzymatic product 15-HETE may regulate transcription by activating the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma). 15-LOX-2 and 15-HETE formation are reduced in prostate carcinoma. The distribution of 15-LOX-2 in the normal lung and its expression in lung carcinomas has not been reported and was investigated in the current study by using immunohistochemistry and tissue microarrays (TMAs). In benign lung, 15-LOX-2 immunostaining was noted exclusively in type II pneumocytes, which are known to express PPARgamma. Of 160 lung carcinomas, 15-LOX-2 was expressed in non-small cell carcinomas (NSCLC), including 33 of 69 (48%) adenocarcinomas, with 10 of 16 (63%) bronchioloalveolar carcinomas immunopositive. Fourteen of 55 (25%) squamous cell carcinomas and 2 of 14 (14%) large cell carcinomas showed weak immunostaining. All 19 neuroendocrine tumors were negative. Better differentiated NSCLCs showed greater 15-LOX-2 expression, with a significant inverse correlation between 15-LOX-2 immunostaining and tumor grade (P < 0.03). A significant inverse correlation was also noted between 15-LOX-2 immunostaining and tumor cell proliferation (Ki-67 immunostaining; P < 0.0001). These findings suggest a possible role of 15-LOX-2 in regulating secretory differentiation and proliferation in benign lung and NSCLCs, particularly adenocarcinomas.

Forkhead box A2 transcription factor is expressed in all types of neuroendocrine lung tumors.

Forkhead box A2 (Foxa2) is a winged helix nuclear transcription protein that regulates the expression of genes that are critical to lung morphogenesis, differentiation, and function, including thyroid transcription factor-1, surfactant proteins, and Clara cell secretory protein. We examined the immunoreactivity of Foxa2 in paraffin sections of 75 lung tumors: 17 typical carcinoids, 2 atypical carcinoids, 4 large cell neuroendocrine (NE) carcinomas, 23 small cell carcinomas, 19 adenocarcinomas, 7 squamous cell carcinomas, and 3 (non-NE) large cell carcinomas, using a polyclonal rabbit Foxa2 antibody and a biotin-streptavidin detection system. In the adjacent lung, Foxa2 was detected in normal and hyperplastic type II cells. Foxa2 immunoreactivity was detected in 13 typical carcinoids (76%), 2 atypical carcinoids (100%), 2 large cell NE carcinomas (50%), 11 small cell carcinomas (48%), and 1 adenocarcinoma (5%). Squamous cell carcinomas and (non-NE) large cell carcinomas uniformly lacked Foxa2 staining. Expression of Foxa2 in the entire spectrum of NE lung tumors is another indication of differentiation shared by typical carcinoid, atypical carcinoid, large cell NE carcinoma, and small cell carcinoma.

Overexpression of 12/15-lipoxygenase, an ortholog of human 15-lipoxygenase-1, in the prostate tumors of TRAMP mice.

Changes in the expression and activity of lipid-metabolizing enzymes, including the linoleic acid (LA)-metabolizing enzyme 15-lipoxygenase-1 (15-LO-1), may play a role in the development and progression of human prostate carcinoma (PCa). We reported that human 15-LO-1 (designated as leukocyte type 12-LO or 12/15-LO in mouse) is expressed in human prostate and increased in PCa, particularly high-grade PCa. Genetically engineered mouse (GEM) models of PCa could facilitate the study of this gene and its regulation and function in PCa progression. In this study, we examine the protein expression and enzyme activity levels of 12/15-LO associated with PCa progression in the TRansgenic Adenocarcinoma of Mouse Prostate (TRAMP) model of PCa. This GEM model develops prostatic intraepithelial neoplasia (PIN), followed by invasive gland-forming PCa and invasive and metastatic less differentiated PCa, with neuroendocrine (NE) differentiation (NE Ca). In the wild-type and TRAMP prostates, the most prominent LA metabolite was 13-hydroxyoctadecadienoic acid (13-HODE). Lesser amounts of 12-hydroxyeicosatetraenoic acid and 15-hydroxyeicosatetraenoic acid (HETE) were made from arachidonic acid (AA). In TRAMP prostates, 12/15-LO activity was increased compared to wild type at 20, 29, 39, and 49 weeks, as assessed by LA conversion to 13-HODE, and by AA conversion to 12/15-HETE, respectively. Immunostaining demonstrated that the increased capacity to generate 13-HODE was paralleled by an increase in neoplastic epithelial expression of 12/15-LO in PIN and invasive carcinomas. In conclusion, although there is a basal 12/15-LO activity in the wild-type mouse prostate, there is a marked increase in the expression of 12/15-LO with TRAMP PCa progression, paralleling our previously reported increased expression of the ortholog 15-LO-1 in high-grade human PCa. Thus, 12/15-LO and LA metabolism in the TRAMP model shares similarities to human PCa, and may allow to confirm a role for LA metabolism and other biologic functions of 15-LO-1 in human PCa. In addition, the TRAMP model will serve as a tool for testing the suitability of 12/15-LO-and ultimately human 15-LO--as a therapeutic target during PCa progression.

Metaplastic spindle cell breast tumors arising within papillomas, complex sclerosing lesions, and nipple adenomas.

Micropapillomas/papillomas and complex sclerosing lesions of the breast have been associated with a slightly increased risk for subsequent carcinoma, although benign squamous metaplasia and reactive hypercellular stroma are seen within these lesions. There are few reports of these fibrosclerotic lesions associated with metaplastic tumors. Here we describe a series of metaplastic tumors arising within fibrosclerotic breast lesions. Thirty-three metaplastic tumors associated with fibrosclerotic lesions were selected from a breast pathology consultative practice. Relevant clinical and pathological features were reviewed. Representative sections were evaluated immunohistochemically for expression of cytokeratins, vimentin, and smooth muscle and muscle-specific actins. Both the metaplastic component (spindled and squamous cells) and the glandular elements were graded. The metaplastic tumors arose within papillomas (20 cases), complex sclerosing lesions (7 cases), both papilloma and complex sclerosing lesions (3 cases), and nipple adenoma (3 cases). A majority of the metaplastic tumors showed a dominant spindle cell component with various degrees of atypia, ranging from fibromatosis-like (16 cases) to low-grade (13 cases), intermediate-grade (2 cases), and high-grade (2 cases) fibrosarcoma phenotype. Squamous metaplasia was present in 25 cases, and low-grade glandular elements, in 21 cases. Eleven tumors had a low-grade adenosquamous growth pattern. Ductal carcinoma in situ was present in 7 cases, and invasive mammary carcinoma, in 5 cases. The very low-grade tumors were histologically similar to limited areas of stromal reaction and myofibroblastic proliferation, seen in partially sclerotic micropapillomas/papillomas and complex sclerosing lesions, but usually more cellular. Cytokeratin positivity (13+/13 tested) supports the metaplastic nature of the more plump spindled cells. The spindle cells were also positive for vimentin (8+/8 tested) and smooth muscle (2+/5 tested) and muscle-specific actins (6+/6 tested). Spindle cell metaplastic tumors, from fibromatosis-like to fibrosarcoma, may arise within a variety of fibrosclerotic breast lesions.

Elevated expression of 12/15-lipoxygenase and cyclooxygenase-2 in a transgenic mouse model of prostate carcinoma.

Changes in expression of arachidonic acid (AA) metabolizing enzymes are implicated in the development and progression of human prostate carcinoma (Pca). Transgenic mouse models of Pca that progress from high-grade prostatic intraepithelial neoplasia (HGPIN) to invasive and metastatic carcinoma could facilitate study of the regulation and function of these genes in Pca progression. Herein we characterize the AA-metabolizing enzymes in transgenic mice established with a prostate epithelial-specific long probasin promoter and the SV40 large T antigen (LPB-Tag mice) that develop extensive HGPIN and invasive and metastatic carcinoma with neuroendocrine (NE) differentiation. Murine 8-lipoxygenase (8-LOX), homologue of the 15-LOX-2 enzyme that is expressed in benign human prostatic epithelium and reduced in Pca, was not detected in wild-type or LPB-Tag prostates as determined by enzyme assay, reverse transcription-PCR, and immunohistochemistry. The most prominent AA metabolite in mouse prostate was 12-HETE. Wild-type prostate (dorsolateral lobe) converted 1.6 +/- 0.5% [(14)C]AA to 12-HETE (n = 7), and this increased to 8.0 +/- 4.4% conversion in LPB-Tag mice with HGPIN (n = 13). Quantitative real-time reverse transcription-PCR and immunostaining correlated the increased 12-HETE synthesis with increased neoplastic epithelial expression of 12/15-LOX, the leukocyte-type (L) of 12-LOX and the murine homologue of human 15-LOX-1. Immunostaining showed increased L12-LOX in invasive carcinoma and approximately one-half of metastatic foci. COX-2 mRNA was detectable in neoplastic prostates with HGPIN but not in wild-type prostate. By immunostaining, COX-2 was increased in the neoplastic epithelium of HGPIN but was absent in foci of invasion and metastases. We conclude that (a) AA metabolism in wild-type mouse prostate differs from humans in the basal expression of LOXs (15-LOX-2 in human, absence of its 8-LOX homologue in mouse prostate); (b) increased expression of 12/15-LOX in HGPIN and invasive carcinoma of the LPB-Tag model is similar to the increased 15-LOX-1 in high-grade human Pca; and (c) the LPB-Tag model shows increased COX-2 in HGPIN, and therefore, it may allow additional definition of the role of this enzyme in the subset of human HGPINs or other precursor lesions that are COX-2 positive, as well as investigation of its contribution to neoplastic cell proliferation and tumor angiogenesis in Pca.