Citations

Abstract Recent molecular and pathologic evidence indicate that high-grade serous carcinomas of the ovary, which are the most common type of epithelial carcinomas, may arise from the distal part of fallopian tubes or tubal carcinoma implants. Oviductal glycoprotein 1 (Ovgp1), a glycosylated protein found in the epithelial cells in the oviduct, is the only specific tubal marker so far. Ovgp1 promoter-driven SV40 large T-antigen transgenic mice develop tumors in the female reproductive organs. To characterize these tumors, we performed immunohistochemical analysis in paraffin-embedded sections. Mice were sacrificed at 8 or 13 weeks old. Macroscopically we observed large tumors in the uterus and cervix and markedly enlarged region in the oviduct. Due to the large tumor in the uterus and cervix, we could not keep the mice longer than 13 weeks. Histologically, there were no major differences in these affected regions between 8 weeks old and 13 weeks old mice. We observed, (i) relatively small ovaries and ovarian follicular hyperplasia, (ii) intact ovarian surface epithelium showing no atypical histology, (iii) atypical epithelial hyperplasia within the oviduct (with endometrioid architectural and cytologic features), (iv) leiomyosarcomatous proliferation in the myometrium, and (v) squamous carcinoma in situ in the cervix or early invasive cervical cancer with extensive papillary architecture. We did not detect metastasis from the tumor to other organs. The atypical abnormalities of the oviduct were more significant in the proximal site to the uterus than the distal site. The proximal oviduct demonstrated weak and spotty p53 expression, beneath the epithelium, similar to p53 signature in the human oviduct. We hypothesized that stem cell components may contribute to the tumor development and that putative cancer stem cells could be identified by stem cell markers. In the oviduct epithelium, Bmi1 expression was not detectable. Cytoplasmic expression of Sox2 was observed in all epithelial cells of the oviduct. There was little correlation between Sox2/Bmi1 staining and p53 staining in the oviduct. Interestingly, Sox2 and Bmi1 staining in the wild-type control mice showed immunoreactive cells interspersed between glandular structures, a pattern similar to previously described label-retaining cells in the endometrium. The expression pattern in Ovgp1-SV40 mice, Bmi1 and Sox2 expression were more obvious in the endometrial stromal area but not in the leiomyosarcoma region, which implies that stem cell components in the endometrial region may support the leiomyosarcoma progression in this mouse model. In conclusion, Ovgp1-SV40 transgenic mouse is a useful model for studies involving fallopian and lower genital tract carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3272. doi:1538-7445.AM2012-3272

Abstract Background: Cigarette smoking (CS) is an established colorectal cancer (CRC) risk factor. The p53 protein, encoded by the TP53 tumor suppressor gene that is commonly mutated in CRC, is important in cell cycle arrest needed to repair DNA damage or induce apoptosis to prevent tumor propagation. In this prospective cohort study, we examined CS-associated CRC risks by p53 protein expression level in the population-based Iowa Women's Health Study (IWHS). Methods: The IWHS recruited 41,836 randomly selected Iowa women, ages 55-69 years, with a valid driver's license at study entry (1986). CS and other exposure variables were assessed at baseline, by self-report. Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 CRC cases diagnosed through 12/31/2002. CS was categorized by smoking status (never, current, former), average number of cigarettes per day (1-19, 20-39, > 40) and cumulative pack-years (1-19, 20-39, > 40). P53 protein expression was determined by immunohistochemistry on tissue microarrays. Tumor cores were scored by combining both staining intensity and percent of cells stained to determine negative, low or high p53 protein expression levels. Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confidence intervals (CIs). Results: Of the 732 available CRC cases, 486 (66%) had complete CS and p53 data. Associations between CS and CRC subtypes defined by p53 expression level are shown in the Table. Conclusions: These data demonstrate no clear heterogeneity of CS with CRC subtypes defined by p53 expression levels among older women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1677. doi:1538-7445.AM2012-1677

Abstract Background: Cigarette smoking (CS) is an established colorectal cancer (CRC) risk factor. The p53 protein, encoded by the TP53 tumor suppressor gene that is commonly mutated in CRC, is important in cell cycle arrest needed to repair DNA damage or induce apoptosis to prevent tumor propagation. In this prospective cohort study, we examined CS-associated CRC risks by p53 protein expression level in the population-based Iowa Women's Health Study (IWHS). Methods: The IWHS recruited 41,836 randomly selected Iowa women, ages 55-69 years, with a valid driver's license at study entry (1986). CS and other exposure variables were assessed at baseline, by self-report. Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 CRC cases diagnosed through 12/31/2002. CS was categorized by smoking status (never, current, former), average number of cigarettes per day (1-19, 20-39, > 40) and cumulative pack-years (1-19, 20-39, > 40). P53 protein expression was determined by immunohistochemistry on tissue microarrays. Tumor cores were scored by combining both staining intensity and percent of cells stained to determine negative, low or high p53 protein expression levels. Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confidence intervals (CIs). Results: Of the 732 available CRC cases, 486 (66%) had complete CS and p53 data. Associations between CS and CRC subtypes defined by p53 expression level are shown in the Table. Conclusions: These data demonstrate no clear heterogeneity of CS with CRC subtypes defined by p53 expression levels among older women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1676. doi:1538-7445.AM2012-1676

Abstract Background: Colon cancer is categorized by the acquisition of a number of molecular alterations in both oncogenes and in tumor suppressor genes. Although cMYC alterations have been reported in colon cancer cell lines, little other information exists in primary colon tumors. We sought to determine the frequency of cMYC amplification in primary colon cancer and its relationship to other well defined colon tumor alterations. Methods: An initial set of 392 tumors were evaluated. All samples were tested for the BRAF V600E mutation and all were classified as proficient mismatch repair (pMMR) based on both IHC and microsatellite analysis of tumor tissue. A second set of 522 tumors was selected to replicate associations identified in the first set of samples. Similar to the initial cohort, both the BRAF V600E and the mismatch repair status of the tumors were assessed. The second cohort, however, included tumors that were both pMMR and dMMR. In both sets of samples, fluorescent in situ hybridization was used to evaluate cMYC gene amplification. Results: In cohort 1, cMYC amplification was observed in 15 of the 362 (4%) pMMR tumors successfully analyzed (Table 1). cMYC amplification was detected in 10 of 323 (3%) tumors with normal BRAF status vs. 5 of 39 (13%) tumors with altered BRAF status (p=0.015). In the second cohort, cMYC amplification was found in 20 of the 522 (4%) tumors. Only 1 of the 152 (<1%) dMMR tumors had cMYC amplification vs. 19 of the 370 (5%) pMMR tumors (p=0.012). Of the pMMR tumors, cMYC amplification was detected in 13 of 333 (4%) tumors with normal BRAF status vs. 6 of 37 (16%) tumors with altered BRAF status (p=0.007), nearly identical to the first group. Conclusion: cMYC amplification in colon cancer is an infrequent event. However, when present, cMYC amplification occurs almost exclusively in tumors that are pMMR. Additionally, among pMMR tumors, cMYC amplification is associated with the presence of the BRAF V600E mutation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1151. doi:1538-7445.AM2012-1151

Abstract Background: Colorectal cancer (CRC) is a molecularly heterogeneous disease. Three molecular pathways (traditional, serrated and alternate) have been recently proposed based on integrated combinations of microsatellite instability (MSI), CpG island methylation phenotype (CIMP), BRAF mutation, and KRAS mutation status (Gastroenterol 2010;138:2088-2100). To our knowledge, clinicopathologic associations with these CRC pathways have not been previously described. Methods: Data and tissue resources were obtained from the population-based Iowa Women's Health Study, which recruited 41,836 randomly selected women, ages 55-69 years, at study entry (1986). Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 CRC cases diagnosed through 12/31/2002. Established laboratory methods were used to characterize CRC cases by MSI (MSS/MSI-L or MSI-H), CIMP (neg, low, or high), BRAF mutation (wt or mut), and KRAS mutation (wt or mut) status. Molecular pathways were defined as: traditional (MSS/MSI-L, CIMP-neg, BRAF wt, and KRAS wt); serrated (any MSI, CIMP-high, BRAF mut, and KRAS wt), alternate (MSS/MSI-L, CIMP-low, BRAF wt, and KRAS mut), or other pathway. Chi-square tests and analyses of variance were used to compare clinicopathologic features at CRC presentation (age, anatomic subsite, tumor grade, and SEER stage) across the molecular pathways. Results: Comlete and informative MSI, CIMP, BRAF and KRAS data were obtained for 491/732 (67%) CRC cases. Clinicopathologic associations are shown in the Table. Conclusions: These data suggest that distributions of age at diagnosis, subsite, and tumor grade, but not SEER stage, differ across the traditional, serrated, and alternate carcinogenic pathways, which may have implications for molecularly-targeted CRC prevention and/or therapy strategies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5518. doi:1538-7445.AM2012-5518

Abstract Background: Despite recent advances in prevention and therapy, colorectal cancer (CRC) continues to account for nearly 50,000 deaths per year in the US. TNM stage is the current CRC prognostic standard, yet within-stage prognostic heterogeneity is well documented. Microsatellite instability (MSI), CpG island methylation phenotype (CIMP), and BRAF- and KRAS-mutation status represent candidate prognostic markers. However, associations between these markers and CRC survival have not been described in a population-based setting. Methods: Data and tissue resources were obtained from the Iowa Women's Health Study (IWHS), which recruited 41,836 women, ages 55-69 years, at study entry (1986). Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 representative CRC cases diagnosed through 12/31/2002. Established laboratory methods were used to characterize CRC cases: MSI-H or MSS/MSI-L (by instability in β3 vs. <3 out of 10 markers, respectively); CIMP+ or CIMP− (by promoter hypermethylation in β3 vs. 0-2 out of 5 genes, respectively); BRAFwt or BRAFmut (by fluorescent allele specific PCR to detect the V600E point mutation in exon 15); and KRASwt or KRASmut (by direct sequence analysis of codons 12 and 13 in exon 2). Cox regression models were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for time to death of any cause adjusted for age, stage, grade, and treatment status. Results: CRC cases with informative molecular marker data ranged from 515/732 (70%) for KRAS to 548/732 (75%) for MSI status. Mean follow-up was 4.4 years for deceased individuals and 11.2 years for women alive at last contact. After multivariable adjustment, both MSS/MSI-L (p=0.004) and KRASmut (p=0.048) tumors were associated with poorer survival. Survival did not significantly differ across levels of CIMP and BRAF status. Conclusions: MSI and KRAS status may influence CRC survival among older women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4492. doi:1538-7445.AM2012-4492

Abstract Hyperactivation of EGFR/HER2/K-RAS is often associated with reduced cell/focal adhesion, altered cell junctions, increased cell motility, and enhanced invasion/metastasis in a large percentage of human cancers. Finding novel measures that inhibit activated ERBB/K-RAS signals and, thus, reverse tumorigenesis and metastasis remains an important goal in cancer biology. Instead of targeting an upstream component in the EGFR/HER2/K-RAS pathway, we have targeted the most downstream signaling module, called the SIAH-dependent proteolytic machinery. SIAH/SINA are evolutionarily conserved RING E3 ligases that act as an essential “gatekeeper” signaling module in the RAS signal transduction pathway. We have demonstrated that proper SIAH function is required for K-RAS signal transduction. SIAH is a novel and tumor-specific biomarker for proliferating cells in human cancer. Furthermore, we have shown that SIAH2 inhibition can successfully block both tumorigenesis and metastasis in eleven of the most aggressive human cancer cell lines known in athymic nude mice. These observations highlight the importance of SIAH2 in K-RAS-dependent tumorigenesis and metastasis in human cancer. To elucidate the molecular mechanism of SIAH2 action in human cancer cells, a proteomic approach was taken to identify novel SIAH2-interacting proteins in three highly aggressive human cancer cell lines carrying K-RAS mutations (MiaPaCa, A549 and MDA-MB-435). From these studies, three focal adhesion LIM domain proteins (LPXN, TRIP6 and FHL2) were found to interact with SIAH2 endogenously in these human cancer cells. Here, we provide extensive biochemical evidence demonstrating that SIAH2 interacts with, ubiquitinates and degrades TRIP6/FHL2/LPXN in a dose-dependent fashion, both exogenously and endogenously. This study clearly demonstrates that LPXN, TRIP6 and FHL2 are bona fide SIAH2 substrates in vivo. Ectopic expression of LPXN/TRIP6/FHL2 successfully rescued the defects in cell motility and tumor growth observed in these SIAH2-deficient human cancer cells. These focal adhesion LIM domain proteins may, therefore, represent a novel class of SIAH2 substrates (logical RAS targets) that function downstream of SIAH2 and modulate focal adhesion, increased cell motility, invasion, tumorigenesis and metastasis in response to active ERBB/K-RAS signals. The identification of SIAH2 as an important regulator of focal adhesion and cell motility downstream of K-RAS pathway may help to explain the well-documented changes in cell adhesion, aggressive tumor growth, invasion and metastasis in response to K-RAS pathway activation in the most lethal forms of human cancers. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2335. doi:10.1158/1538-7445.AM2011-2335