Preneoplastic Changes Research Articles

Significance of immunohistochemical expression of p16INK4a in the differentiation of inflammatory and preneoplastic cervical lesions.

Most studies point at the main role of humanpapilloma virus (HPV) in the development of dysplasia and cervical cancer. Due to the low specificity and sensitivity of morphological diagnostic methods it is necessary to find an adequate marker which would be introduced in the screening program for cervical cancer. Most research suggests that p16INK4a is a specific and sensitive marker. The aim of this research was to determine the presence of p16INK4a expression in inflammatory and preneoplastic lesions of the cervix. The study was performed on 73 samples of cervical biopsy. In 34 patients a preneoplastic change (dysplasia) in the stratified squamous cervix epithelium was found, and in 39 a non-specific inflammatory process was disclosed. In all samples, immunohistochemical analysis using antibodies to p16INK4a was performed. The expression of p16INK4a was verified in 67.65% of cases in dysplastic cervical lesions and 38.5% of the inflammatory lesions. A statistically significant difference was determined in the presence and grade of expression between dysplastic and inflammatory lesions of the cervix (χ2 = 24.16; p < 0.001). The expression was more frequent and had a higher grade in dysplastic lesions with high grade and showed a statistically significant difference compared to the expression in low-grade dysplasia (χ2 = 21.48; p < 0.001). The analysis of the presence of p16INK4a can differentiate non-neoplastic from preneoplastic changes in the cervix. It is recommended to use immunocytochemical and immunohistochemical analysis using p16INK4a in interpreting borderline lesions of the cervix.

Papillomatosis as a criteria for the formation of the group at risk of laryngeal cancer

The objective of the present study was to determine the incidence of dysplastic pre-neoplastic alterations in the patients presenting with papillomatosis. The results of the clinical, endoscopic, and morphological examination of 42 patients presenting with laryngeal papillomas made it possible to diagnose grade II-III laryngeal cancer in 7 (16.7%) patients. Half of them exhibited pre-neoplastic changes in laryngeal mucosa. The following criteria for the formation of laryngeal cancer risk groups, besides grade II-III epithelial dysplasia, were identified: long (over 12 months) history of papillomatosis, human papilloma virus infection, the history of smoking over 20 years, professional contacts with petroleum, oil, and lubrication materials, and the male gender. An algorithm of observation and treatment for each group of patients differing in the degree of dysplastic changes in laryngeal mucosa was proposed. It is concluded that adequate clinical and endoscopic monitoring of the patients at risk of laryngeal cancer makes it possible to increase the frequency of detection of this condition at the early stages of its development.

PELP1 overexpression in the mouse mammary gland results in the development of hyperplasia and carcinoma.

Estrogen receptor (ER) coregulator overexpression promotes carcinogenesis and/or progression of endocrine related-cancers in which steroid hormones are powerful mitogenic agents. Recent studies in our laboratory, as well as others, demonstrated that the estrogen receptor coregulator PELP1 is a proto-oncogene. PELP1 interactions with histone demethylase KDM1 play a critical role in its oncogenic functions and PELP1 is a prognostic indicator of decreased survival in patients with breast cancer. However, the in vivo significance of PELP1 deregulation during initiation and progression of breast cancer remains unknown. We generated an inducible, mammary gland-specific PELP1-expressing transgenic (Tg) mouse (MMTVrtTA-TetOPELP1). We found more proliferation, extensive side branching, and precocious differentiation in PELP1-overexpressing mammary glands than in control glands. Aged MMTVrtTA-TetOPELP1 Tg mice had hyperplasia and preneoplastic changes as early as 12 weeks, and ER-positive mammary tumors occurred at a latency of 14 to 16 months. Mechanistic studies revealed that PELP1 deregulation altered expression of a number of known ER target genes involved in cellular proliferation (cyclin D1, CDKs) and morphogenesis (EGFR, MMPs) and such changes facilitated altered mammary gland morphogenesis and tumor progression. Furthermore, PELP1 was hyper-phosphorylated at its CDK phosphorylation site, suggesting an autocrine loop involving the CDK-cyclin D1-PELP1 axis in promoting mammary tumorigenesis. Treatment of PELP1 Tg mice with a KDM1 inhibitor significantly reduced PELP1-driven hyperbranching, reversed alterations in cyclin D1 expression levels, and reduced CDK-driven PELP1 phosphorylation. These results further support the hypothesis that PELP1 deregulation has the potential to promote breast tumorigenesis in vivo and represent a novel model for future investigation into molecular mechanisms of PELP1-mediated tumorigenesis.

Preneoplastic Conditions in the Stomach: Always a Point of No Return

Gastric atrophy (GA) and intestinal metaplasia are defined preneoplastic conditions of the stomach, whereas Helicobacter pylori gastritis by itself represents a risk condition for gastric cancer (GC) development. After H. pylori eradication, an overall reduction of GC incidence has been shown. However, this effect is lost once H. pylori gastritis has evolved to severe GA. On the other hand, only up to 5% of patients with severe GA may develop intestinal-type GC, and therefore the so-called ‘point of no return' may not be appropriate to define the condition of all patients carrying preneoplastic changes in the gastric mucosa. Patients with the highest risk for GC are those who have already had GC that was cured by endoscopic resection. Prospective trials on the effect of H. pylori eradication in this high-risk group of patients showed inconsistent results, probably because of the inclusion of patients with and without baseline severe GA. Severe fundic GA determined by means of histology or serology represents the condition with the highest risk for metachronous neoplastic lesions in the stomach. In the present review, we focus on the effects of H. pylori eradication in patients with severe atrophy in terms of GC prevention.

Abnormal cervicovaginal cytology, unsatisfactory colposcopy and the use of vaginal estrogen cream: an observational study of clinical outcomes for women in low estrogen states.

To determine the effectiveness of vaginal estrogen cream to improve the rate of satisfactory colposcopy and subsequent smear result in patients in a hypoestrogenic state and an abnormal Papanicolaou smear. To delineate between abnormal smears secondary to atrophy and inflammation from preneoplastic change and suggest an effective treatment strategy to deal with this challenging situation. Patients with abnormal cervicovaginal smears who were in a low estrogen state (postmenopausal or amenorrheic postnatal) undergoing colposcopy were identified. All patients had an unsatisfactory colposcopy and were treated with vaginal estrogen cream twice per week for 6 weeks and underwent repeat colposcopy, smear and targeted biopsy where required. Fifty-four patients had an abnormal smear and were clinically in a low estrogen state, with four having previously had a hysterectomy. After 6 weeks of vaginal estrogen therapy, 32 out of 50 patients' colposcopic examinations were satisfactory. Also, 40 out of 54 patients' smears returned to normal after treatment. Of the 14 patients with persistent smear abnormalities, only three were diagnosed with true high-grade pre-invasive disease. The use of vaginal estrogen cream for patients with smear abnormalities and a low estrogen status improves the satisfactory colposcopy rate and improves the accuracy of the prediction of true high-grade pre-invasive disease. This treatment may then reduce the number of patients that require definitive treatment for their screen-detected abnormalities in this patient population.

Covering the Cover

Covering the Cover

Gastric cancer--epidemiologic and clinical aspects.

Gastric cancer (GC) continues to be an important health threat as the third leading cause of cancer related death in both sexes worldwide. In a recent analysis, the mortality trends for the time period from 1980 till 2011 were significantly downward in all countries, but the declines in the USA, EU and several other major countries were of low magnitude when compared with the past. Furthermore, the relative contribution of cardia cancers compared with noncardia cancers increased among countries with higher GC rates. With respect to preneoplastic changes of the gastric mucosa, a large population-based study suggests that Helicobacter pylori infection and antigastric parietal cell antibodies-mediated autoimmune response might, for the most part, be independent and follow distinct pathways rather than causally related pathways leading to chronic atrophic gastritis. A large prospective, randomized, open-label Korean trial questioned the role of H.pylori eradication for the prevention of metachronous lesions after endoscopic resection of early GC. A review of 1258 Japanese cases undergoing curative endoscopic submucosa dissection for early GC showed that scheduled follow-up endoscopy is mandatory for detecting metachronous lesions at an early stage, where they can be treated by endoscopic resection. Ramucirumab, a vascular endothelial growth factor receptor-2 antagonist, is the first biological treatment that provides survival benefits to patients with advanced GC in progress after first-line chemotherapy. The target agent rilotumumab is currently being evaluated in patients with advanced GC overexpressing the HGF/c-MET signaling pathway. In the near future, ipilimumab and nivolumab, two immunostimulatory monoclonal antibodies with antineoplastic effects, might offer new therapeutic options for patients with advanced GC.

Population Based Helicobacter pylori Screening and Eradication: Advances Versus Side Effects

Gastric cancer is the fourth most common cancer in the world and second most common reason for cancer related death. Projections for the future predict that gastric cancer incidence will continue to rise. Risk factors for gastric cancer are Helicobacter pylori (H pylori) infection, host genetic factors and environmental factors. H pylori is a class I carcinogen and responsible for 60 % - 80 % of all gastric cancers of intestinal and diffuse type, as well as gastric MALT lymphoma. From animal and intervention studies we know that premalignant gastric lesions development and gastric cancer can be prevented with early H pylori eradication. In countries with gastric cancer incidence higher than 20 / 100 000 per year national screening for H pylori infection and eradication of all H pylori infections should be performed. Type of eradication therapy depends on local antimicrobial resistance rates. Quadruple bismuth or non- bismuth therapies can achive more than 90 % eradication rate. The success of eradication therapy must be controlled with noninvasive test. Patients with extensive preneoplastic changes (atrophy, intestinal metaplasia) should have endoscopic and histologic controls. Endoscopic screening should be performed in intervals according to the risk stratification by OLGA / OLGIM staging system or A-D staging system. In countries with high gastric cancer incidence national screening with serological tests for pepsinogen I (PGI), PGI/PGII ratio and H pylori antibodies can select patients at higher risk for gastric cancer.

Inducible loss of one Apc allele in Lrig1-expressing progenitor cells results in multiple distal colonic tumors with features of familial adenomatous polyposis.

Individuals with familial adenomatous polyposis (FAP) harbor a germline mutation in adenomatous polyposis coli (APC). The major clinical manifestation is development of multiple colonic tumors at a young age due to stochastic loss of the remaining APC allele. Extracolonic features, including periampullary tumors, gastric abnormalities, and congenital hypertrophy of the retinal pigment epithelium, may occur. The objective of this study was to develop a mouse model that simulates these features of FAP. We combined our Lrig1-CreERT2/+ mice with Apcfl/+ mice, eliminated one copy of Apc in leucine-rich repeats and immunoglobulin-like domains protein 1 (Lrig1)-positive (Lrig1(+)) progenitor cells with tamoxifen injection, and monitored tumor formation in the colon by colonoscopy and PET. Initial loss of one Apc allele in Lrig1(+) cells results in a predictable pattern of preneoplastic changes, culminating in multiple distal colonic tumors within 50 days of induction, as well as the extracolonic manifestations of FAP mentioned above. We show that tumor formation can be monitored by noninvasive PET imaging. This inducible stem cell-driven model recapitulates features of FAP and offers a tractable platform on which therapeutic interventions can be monitored over time by colonoscopy and noninvasive imaging.

Su1979 Adenocarcinomas at the Esophagogastric Junction At the Most Distal Location (Siewert Type 3) are More Likely Associated With Preneoplastic Mucosal Changes in the Stomach Than Proximal Tumors

Su1979 Adenocarcinomas at the Esophagogastric Junction At the Most Distal Location (Siewert Type 3) are More Likely Associated With Preneoplastic Mucosal Changes in the Stomach Than Proximal Tumors

High-fat diet alters the oligosaccharide chains of colon mucins in mice

Mucins are high molecular weight epithelial proteins, strongly glycosylated, and are the main component of the mucus. Since mucus secretion can be altered in diseases, colon mucins can be regarded as a biomarker of chronic inflammatory bowel diseases or preneoplastic changes. Conventional histochemistry and lectin histochemistry combined with chemical treatment and enzymatic digestion were carried out to analyze the colon mucins in mice fed a high-fat diet for 25weeks, a period sufficient to induce simple liver steatosis, to check whether the carbohydrate features of mucus can be altered by an inadequate diet. An increase in the sialo/sulfomucins ratio with respect to control mice, assessed by computerized image analysis, was observed in the colon, although differences in sialic acid acetylation between control and mice fed a high-fat diet were not found. High-fat diet was also associated with altered lectin-binding pattern of the mucus, with a probable shortening of oligosaccharide chains of glycoproteins. This pattern was leading to over-expression of Galβ1,3GalNAc terminal dimers (TF antigen) and GalNAc terminal residues (Tn antigen). This altered composition of mucins can be related to a defect in the process of glycosylation, or to incomplete maturation of goblet cells, and may be an early indication of preneoplastic and neoplastic changes. In conclusion, our findings confirm that a fatty-rich diet (Western-style diet) induces alteration of mucins and may be associated with colon diseases. Our investigation corroborates the usefulness of lectins histochemistry in the early diagnosis of prepathological states of the colon.

Highlights of This Issue

Inflammation has long been associated with cancer, and angiopoietin-like protein 2 (ANGPTL2) is known to facilitate inflammatory carcinogenesis and metastasis. In a transgenic mouse model, angptl2-associated inflammation was shown to promote production of reactive oxygen species (ROS), significantly accelerate methylation of the DNA mismatch repair enzyme Msh2 promoter, and decrease expression of Msh2 mRNA, resulting in impaired DNA repair mechanisms. Angptl2 accelerates susceptibility to both “preneoplastic change” and “malignant conversion” due to accumulation of oncogenic DNA mutations, activating chronic inflammation and oxidative stress in the premalignant tissue microenvironment. These findings suggest that Angptl2-induced inflammation increases susceptibility to microenvironmental changes, allowing accumulation of oncogenic DNA mutations.From the multitude of contributing factors implicated in prostate cancer, age and family history rank among the highest. However, despite a number of genetic loci linked to hereditary prostate cancer, no bona fide susceptibility gene has been identified. In the Rapid Impact article for this issue, Labbé and colleagues report on their study of the 20q13 chromosomal region, which had been previously identified as a hereditary prostate cancer susceptibility locus (HPC20) and is now shown in their study to be frequently coamplified with the androgen receptor (AR) in metastatic prostate cancer. High-resolution mapping uncovered AR recruitment hotspots in the 20q13 region. These findings reveal that AR, a primary driver of disease progression, is intimately involved in gene transcription of a known prostate susceptibility locus.The overexpression of miR-221 is a common event in human cancers, with growing evidence supporting its causative role. In this study, Fornari and colleagues identify for the first time the MDM2 oncogene as a direct target of an oncomicroRNA such as miR-221 in cancer tissue. A feed-forward loop sustaining miR-221 aberrant expression was revealed in which miR-221 activates the p53/MDM2 axis by inhibiting MDM2 and, in turn, p53 activation contributes to miR-221 enhanced expression. Moreover, by modulating p53 signaling, miR-221 affects cell-cycle progression and apoptotic response to doxorubicin in hepatocellular carcinoma (HCC)–derived cells, suggesting that miR-221 expression contributes to p53 context-specific response to doxorubicin treatment in HCC.Little is known about tumor initiating cells in oligodendrogliomas, impeding investigation of critical signaling pathways that could be exploited by targeted therapies. Srikanth and colleagues demonstrate that cells with stem-like characteristics are capable of propagating human oligodendrogliomas. Canonical bone morphogenetic protein (BMP) signaling is intact in these cells and potently diminishes their stemness by inducing astrocytic differentiation. Further analyses revealed sequestration of oligodendrocyte differentiation factors OLIG1/2 by BMP-induced ID proteins as a plausible mechanism. These findings elucidate the molecular pathways underlying the effects of BMP signaling on oligodendroglioma stem-like cells and suggest BMP activation as a potential cancer stem cell–targeted therapy in these tumors.

Angiopoietin-like Protein 2 Accelerates Carcinogenesis by Activating Chronic Inflammation and Oxidative Stress

Chronic inflammation has received much attention as a risk factor for carcinogenesis. We recently reported that Angiopoietin-like protein 2 (Angptl2) facilitates inflammatory carcinogenesis and metastasis in a chemically induced squamous cell carcinoma (SCC) of the skin mouse model. In particular, we demonstrated that Angptl2-induced inflammation enhanced susceptibility of skin tissues to "preneoplastic change" and "malignant conversion" in SCC development; however, mechanisms underlying this activity remain unclear. Using this model, we now report that transgenic mice overexpressing Angptl2 in skin epithelial cells (K14-Angptl2 Tg mice) show enhanced oxidative stress in these tissues. Conversely, in the context of this model, Angptl2 knockout (KO) mice show significantly decreased oxidative stress in skin tissue as well as a lower incidence of SCC compared with wild-type mice. In the chemically induced SCC model, treatment of K14-Angptl2 Tg mice with the antioxidant N-acetyl cysteine (NAC) significantly reduced oxidative stress in skin tissue and the frequency of SCC development. Interestingly, K14-Angptl2 Tg mice in the model also showed significantly decreased expression of mRNA encoding the DNA mismatch repair enzyme Msh2 compared with wild-type mice and increased methylation of the Msh2 promoter in skin tissues. Msh2 expression in skin tissues of Tg mice was significantly increased by NAC treatment, as was Msh2 promoter demethylation. Overall, this study strongly suggests that the inflammatory mediator Angptl2 accelerates chemically induced carcinogenesis through increased oxidative stress and decreased Msh2 expression in skin tissue. Angptl2-induced inflammation increases susceptibility to microenvironmental changes, allowing increased oxidative stress and decreased Msh2 expression; therefore, Angptl2 might be a target to develop new strategies to antagonize these activities in premalignant tissue.

The Role of Retinyl Acetate in Chemoprevention

Retinoids have a role in the process of chemoprevention. They can inhibit promotion through inhibiting cell proliferation, enhancing apoptosis and anti-oxidative properties. In the present study initiative-p-dimethylaminoazobenzene (p-DAB) and promotive- 2, 3, 7, 8-Tetrachlorodibenzo-p-Dioxin (TCDD) was given to the rats subchronically. It was aim to evaluate the effects on the apoptosis and lipid peroxidation of Retinyl Acetate in the liver and to determine the plasma levels of Vascular Endothelial Growth Factor (VEGF) and Matrix Metalloproteinase-2 (MMP-2) different fixation intervals called as 30, 60, 90 and 120. Apoptosis was determined with assays of Cytochrome c release and DNA fragmentation. Preneoplastic changes in the liver tissues were evaluated histopathologically. In p-DAB+TCDD group there were a decrease apoptosis and an increase lipid peroxidation, VEGF levels and preneoplastic changes beginning from day 60. The increase of MMP-2 levels was shown at day 90 and 120. There was an increase in the apoptosis and also decrease in the lipid peroxidation and levels of VEGF in the Retiniyl Acetate treated rats compare to p-DAB+TCDD group at day 60, 90, and 120. Mild preneoplastic changes and decreased MMP-2 were also observed only at day 120. Retinyl acetate may affect the stages of promotion that appeared preneoplastic changes via inducing apoptosis, reducing lipid peroxidation in the liver and decreasing levels of pro-angiogenic molecule VEGF and pro-invasive molecule MMP-2.

RUNX2 in subtype specific breast cancer and mammary gland differentiation

RUNX2, a master regulator of osteogenesis, is oncogenic in the lymphoid lineage; however, little is known about its role in epithelial cancers. Upregulation of RUNX2 in cell lines correlates with increased invasiveness and the capacity to form osteolytic disease in models of breast and prostate cancer. However, most studies have analysed the effects of this gene in a limited number of cell lines and its role in primary breast cancer has not been resolved. Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression. We confirm RUNX2 as a gene that has a potentially important functional role in triple-negative breast cancer. To investigate the role of this gene in breast cancer, we made a transgenic model in which Runx2 is specifically expressed in murine mammary epithelium under the control of the mouse mammary tumour virus (MMTV) promoter. We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation. We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

Helicobacter pylori eradication for preventing gastric cancer.

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer (GC) development, which is one of the most challenging malignant diseases worldwide with limited treatments. In the multistep pathogenesis of GC, H. pylori infection slowly induces chronic active gastritis, which progresses through the premalignant stages of atrophic gastritis, intestinal metaplasia, and dysplasia, and then finally to GC. Although eradication of H. pylori is a reasonable approach for the prevention of GC, there have been some contradictory reports, with only some long-term follow-up data showing efficacy of this approach. The inconsistencies are likely due to the insufficient number of participants, relatively short follow-up periods, poor quality of study designs, and the degree and extent of preneoplastic changes at the time of H. pylori eradication. This review analyzes recent high-quality studies to resolve the discrepancies regarding the eradication of H. pylori for GC prevention. The relationship between H. pylori eradication and GC/precancerous lesions/metachronous GC is examined, and the cost-effectiveness of this strategy in the prevention of GC is assessed. Although it is assumed that eradication of H. pylori has the potential to prevent GC, the feasibility and appropriate timing of this strategy for cancer prevention remain to be determined. As a result, additional well-designed trials with longer follow-up periods are needed to clarify this issue.

Bad and Bid – potential background players in preneoplastic to neoplastic shift in human endometrium

The most common malignancies of the female genital tract are endometrial carcinomas, whose are generally proceeded by hyperplasia. The maintenance of tissue homeostasis is to great extent governed by apoptosis, whose defects can lead to the preneoplastic and/or cancerous changes. Endometrial apoptosis involves among others three groups of proteins of the Bcl-2 family. First group contains anti-apoptotic proteins (e. g. Bcl-2, Bcl-xL). The other two groups belong to the pro-apoptotic proteins with three (e. g. Bax, Bak) or one (e. g. Bad, Bid) so-called BH domains. Bad and Bid trigger the oligomerization of Bak and Bax protein, which permeabilize the outer mitochondrial wall. Unlike Bid, Bad cannot directly trigger apoptosis. Instead, Bad lowers the threshold at which apoptosis is induced, by binding anti-apoptotic Bcl-2 proteins. However, their mutual counterbalance or synergism in the human endometrium has not been reported yet.In this study, the levels of Bid and Bad were measured using SDS-PAGE and Western blotting with specific antibodies, with the aim to analyse expression of Bid and Bad proteins in normal (NE), hyperplastic (HE) and cancerous (CE) endometrium. We demonstrated that Bid expression in CE reached only 47% and 50% of this observed in NE and HE. Conversely, Bad expression in HE reached only 40% and 36% of this observed in NE and CE, respectively. We detected no significant changes of Bid expression between HE and NE, and levels of Bad protein were not different between CE and NE.Trend of Bid and Bad protein expression is clearly opposite in HE and CE. We hypothesise that disrupted apoptotic program in CE seems to be reduced further by lowering levels of direct apoptotic trigger protein Bid. We suggest that the adenocarcinoma tissue of human endometrium thus tries to strengthen its apoptotic effort by lowering the apoptotic threshold via higher Bad levels.

Abstract P2-05-01: Induction of PELP1 expression in mammary gland promotes tumorigenesis by enhancing CDK-CyclinD1 signaling

Abstract Introduction: Estrogen receptor coregulator over-expression promotes carcinogenesis and/or progression of endocrine related-cancers where steroid hormones are powerful mitogenic agents. Recent studies in our laboratory as well as others demonstrated that PELP1 is a proto-oncogene and a prognostic indicator of decreased survival in breast cancer patients. Recent studies indicated that PELP1 is needed for optimal epigenetic modifications at ER target genes and PELP1 interactions with KDM1 play a key role in PELP1 mediated oncogenic functions. However, the in vivo significance of PELP1 deregulation during initiation and progression of breast cancer remains unknown. The objective of this study is determine the molecular mechanisms by which PELP1 regulate breast cancer progression in vivo. Method: To determine the significance of PELP1 over-expression in mammary tumorigenesis, we used an inducible, tissue-specific PELP1 expressing transgenic mouse. Mammary epithelial-specific expression of PELP1 was validated by immunohistochemistry and Western blot analysis. PELP1-mediated morphological and histological changes were analyzed by examining carmine-stained whole mounts and H&amp;E-stained paraffin embedded mammary glands sections. Differential expression of breast cancer-focused genes between wild type and PELP1 transgenic mammary glands was determined using real-time RT2 Profiler PCR array. Proliferation was analyzed using Ki-67 immuno staining. RTqPCR, Western and IHC analysis were used to confirm the changes in the expression of PELP1 regulated genes. Results: We observed an increase in proliferation, extensive side branching and precocious differentiation in PELP1 expressing mammary gland compared to controls. Aged MMTVrtTA-TetOPELP1 bitransgenic mice revealed hyperplasia and preneoplastic changes as early as 12 weeks and mammary tumors occurred at a latency of 10.5 months. Mechanistic studies using tissues from control and PELP1 transgenic mice revealed that PELP1 deregulation modulates expression of a number of known ER target genes involved in cellular proliferation (such as cyclin D1, CDKs) and morphogenesis (EGFR, MMPs) and such changes facilitated altered mammary gland morphogenesis and tumor progression. Western and IHC analysis of mammary glands confirmed upregulation of CDK and Cyclin D1 protein levels in PELP1 Tg mice. Further, PELP1 is hyperphosphorylated at CDK phosphorylation site in PELP1 (Ser 991), suggesting an autocrine loop involving CDk-CyclinD1-PELP1 axis in promoting mammary tumorigenesis. Treatment of PELP1 Tg mice with pargyline, an inhibitor of KDM1 for four months significantly reduced PELP1 driven hyperplasia. Mechanistic studies revealed that pargyline treatment reduced cyclin D1 expression levels and substantially reduced CDK driven PELP1 phosphorylation. Conclusions: PELP1 deregulation modulates expression of a number of known ER target genes and cancer promoting genes. PELP1 mediated epigenetic changes via KDM1 play role in PELP1 oncogenic functions in vivo. Collectively, these results support that PELP1 deregulation has potential to promote breast tumorigenesis in vivo. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-05-01.

Histopathological and ultrastructural perturbations in tilapia liver as potential indicators of pollution in Lake Al-Asfar, Saudi Arabia

Lake Al-Asfar (Al-Hassa, Saudi Arabia) is under threat from contaminants released through human activities such as agriculture and urban and industrial developments. In the present study, histopathologic and ultrastructural changes in liver of tilapia Oreochromis niloticus were analyzed to monitor the possible impact of pollution in Al-Asfar estuary. Heavy metals such as Ni, Fe, Zn, Co, Ba, Pb, and Cd were predominant in the lake water and far exceeded the international permissible limits. In fish samples, high prevalences of preneoplastic changes (50 %) and one case of cholangiocarcinoma were revealed in liver tissues. Cytological damage in fish hepatocytes included glycogen exhaustion, deformation of nuclear envelope, heterochromatin condensation, mitochondrial degeneration, vesiculation of rough endoplasmic reticulum, augmentation of smooth endoplasmic reticulum, and lysosomal proliferation. In conclusion, the observed biomarker responses were potential indicators of health impairment or disease in field fish populations, although there was no direct proof of a simple cause-effect relationship. This is the first biological effect assessment in Lake Al-Asfar using tilapia as suitable target species.

Fhit Deficiency-Induced Global Genome Instability Promotes Mutation and Clonal Expansion

Loss of Fhit expression, encoded at chromosome fragile site FRA3B, leads to increased replication stress, genome instability and accumulation of genetic alterations. We have proposed that Fhit is a genome ‘caretaker’ whose loss initiates genome instability in preneoplastic lesions. We have characterized allele copy number alterations and expression changes observed in Fhit-deficient cells in conjunction with alterations in cellular proliferation and exome mutations, using cells from mouse embryo fibroblasts (MEFs), mouse kidney, early and late after establishment in culture, and in response to carcinogen treatment. Fhit -/- MEFs escape senescence to become immortal more rapidly than Fhit +/+ MEFs; -/- MEFs and kidney cultures show allele losses and gains, while +/+ derived cells show few genomic alterations. Striking alterations in expression of p53, p21, Mcl1 and active caspase 3 occurred in mouse kidney -/- cells during progressive tissue culture passage. To define genomic changes associated with preneoplastic changes in vivo, exome DNAs were sequenced for +/+ and -/- liver tissue after treatment of mice with the carcinogen, 7,12-dimethylbenz[a]anthracene, and for +/+ and -/- kidney cells treated in vitro with this carcinogen. The -/- exome DNAs, in comparison with +/+ DNA, showed small insertions, deletions and point mutations in more genes, some likely related to preneoplastic changes. Thus, Fhit loss provides a ‘mutator’ phenotype, a cellular environment in which mild genome instability permits clonal expansion, through proliferative advantage and escape from apoptosis, in response to pressures to survive.