Proliferation, apoptosis and their regulatory protein expression in colorectal adenomas and serrated lesions.

BACKGROUND: Adenomas and serrated lesions represent heterogeneous sets of early precursors in the colorectum with varying malignant potential. They are often distinguished by their histopathologic differences, but little is known about potential differences in regulation of epithelial proliferation and apoptosis. METHODS: We conducted a protein expression analysis using tissue microarrays of 625 colorectal adenomas and 142 serrated lesions to determine potential differences in regulation of epithelial proliferation and apoptosis. We quantitated proliferation with Ki-67; apoptosis with activated caspase-3 (CASP3); up- and down-regulators of proliferation with cyclin D1, p16INK2, and p21Cip1; and apoptosis regulators with BAX, BCL2, and survivin. Linear mixed effects models and circos diagrams were used to determine relationships among expression and lesion characteristics. RESULTS: Adenomas had a significantly higher CASP-3 labeling index (LI) than serrated lesions, resulting in a lower net growth ratio (Ki-67 LI/activated CASP-3 LI, p-value<0.0001). Cyclin D1 LI, p16 LI and p21 LI were lower in adenomas compared to serrated lesions, while expression of both BCL2 and BAX were higher (p <0.001). Among adenomas, cyclin D1 LI and p16 LI levels increased with greater villous component, and the highest BAX expression was detected in adenomas larger than 2 cm (both p<0.0001). Right-sided adenomas had higher CASP3 LI than left colorectal adenomas (p = 0.008). Significant differences in cyclin D1 LI, p21 LI and survivin LI were also observed across histopathologic subtypes of serrated lesions. CONCLUSIONS: Our findings demonstrate different patterns of regulatory protein expression in adenomas than serrated lesions, especially involving apoptosis. ClinicalTrials.gov Identifier: NCT00272324.

Epigenetic Activation of WNT5A Drives Glioblastoma Stem Cell Differentiation and Invasive Growth.

Glioblastoma stem cells (GSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. To illuminate mechanisms governing these hallmark features, we developed a de novo glioblastoma multiforme (GBM) model derived from immortalized human neural stem/progenitor cells (hNSCs) to enable precise system-level comparisons of pre-malignant and oncogene-induced malignant states of NSCs. Integrated transcriptomic and epigenomic analyses uncovered a PAX6/DLX5 transcriptional program driving WNT5A-mediated GSC differentiation into endothelial-like cells (GdECs). GdECs recruit existing endothelial cells to promote peritumoral satellite lesions, which serve as a niche supporting the growth of invasive glioma cells away from the primary tumor. Clinical data reveal higher WNT5A and GdECs expression in peritumoral and recurrent GBMs relative to matched intratumoral and primary GBMs, respectively, supporting WNT5A-mediated GSC differentiation and invasive growth in disease recurrence. Thus, the PAX6/DLX5-WNT5A axis governs the diffuse spread of glioma cells throughout the brain parenchyma, contributing to the lethality of GBM.

Colorectal adenoma stem-like cell populations: associations with adenoma characteristics and metachronous colorectal neoplasia.

Cancer stem cells have tumor-initiation and tumor-maintenance capabilities. Stem-like cells are present in colorectal adenomas, but their relationship to adenoma pathology and patient characteristics, including metachronous development of an additional adenoma ("recurrence"), has not been studied extensively. We evaluated the expression of aldehyde dehydrogenase isoform 1A1 (ALDH1A1), a putative stem cell marker, in baseline adenomas from the placebo arm of chemoprevention trial participants with colonoscopic follow-up. An exploratory set of 20 baseline adenomas was analyzed by ALDH1A1 immunohistochemistry with morphometry, and a replication set of 89 adenomas from 76 high-risk participants was evaluated by computerized image analysis. ALDH1A1-labeling indices (ALI) were similar across patient characteristics and in advanced and nonadvanced adenomas. There was a trend toward higher ALIs in adenomas occurring in the right than left colon (P = 0.09). ALIs of synchronous adenomas were correlated (intraclass correlation coefficient 0.67). Participants in both sample sets who developed a metachronous adenoma had significantly higher ALIs in their baseline adenoma than participants who remained adenoma free. In the replication set, the adjusted odds for metachronous adenoma increased 1.46 for each 10% increase in ALIs (P = 0.03). A best-fit algorithm-based cutoff point of 22.4% had specificity of 75.0% and positive predictive value of 70.0% for metachronous adenoma development. A larger population of ALDH1A1-expressing cells in an adenoma is associated with a higher risk for metachronous adenoma, independent of adenoma size or histopathology. If confirmed, ALDH1A1 has potential as a novel biomarker in risk assessment and as a potential stem cell target for chemoprevention.

Phospho-histone H3 (pHH3) immuno-reactivity as a prognostic marker in non-functioning pituitary adenomas.

Nonfunctioning pituitary adenomas (NFPA) are typically benign neoplasms that can cause significant morbidity through local mass effects. MIB-1/Ki-67 and p53 immuno-reactivity are used to predict aggressive behavior but have known limitations. No marker to date is widely used to reliably predict tumor progression. Phospho-histone H3 (pHH3) is a protein phosphorylated during chromatin condensation in mitosis, and thus anti-pHH3 immunocytochemistry is able to assess mitotic activity. Study objectives were to determine the relationship among pHH3, MIB-1/Ki-67, and p53 in NFPA, and to evaluate the relationship between these indices and time to progression (TTP). Seventy-six patients with NFPA operated on by a single neurosurgeon at University of Texas M. D. Anderson Cancer Center from 1992 to 2006 were identified from a database and met all criteria for inclusion in this clinicopathology study. PHH3, MIB-1/Ki-67, and p53 immuno-reactivity was evaluated in each case. Retrospective review was used to determine TTP. With 282 person-years of follow-up, 19 progression events were observed. A correlation was found between MIB-1/Ki-67 and p53 immuno-reactivity (r = 0.25, p = 0.031). PHH3 did not correlate with either. When markers were dichotomized at the median, only MIB-1/Ki-67 correlated with TPP (log rank p = 0.018). Rank correlation analysis confirmed a significant inverse correlation between both MIB-1/Ki-67 (Dxy = -0.33, p = 0.036) and p53 (Dxy = -0.40, 0.016) immuno-reactivity and TTP. Our results support previous data suggesting that MIB-1/Ki-67 and p53 have clinical utility as prognostic markers for tumor progression. PHH3 did not prove to be associated with TTP in this retrospective study limited by few progression events.

High levels of nucleolar expression of nucleolin are associated with better prognosis in patients with stage II pancreatic ductal adenocarcinoma.

PURPOSE: Nucleolin is a major nucleolar protein that has been shown to be overexpressed in rapidly dividing cells and plays an essential role in cell proliferation and survival. However, the expression and significance of nucleolin in pancreatic ductal adenocarcinoma (PDA) have not been studied. EXPERIMENTAL DESIGN: We used a tissue microarray consisting of 1.0-mm cores of tumor and paired nonneoplastic pancreatic tissue from 69 pancreaticoduodenectomy specimens with stage II PDA. Nucleolin expression was evaluated by immunohistochemistry and scored quantitatively by image analysis. Nucleolin expression was classified as nucleolin-high or nucleolin-low using the median nucleolin labeling index of 3.5% as cutoff. Staining results were correlated with clinicopathologic features and survival. RESULTS: Both PDAs and PDA cell lines showed nucleolar staining for nucleolin. Nucleolin expression was higher in PDAs and PDA cell lines than in nonneoplastic ductal epithelial cells. Among the 69 stage II PDAs, 34 (49%) were nucleolin-high. The median overall survival was 65.2 +/- 16.3 months for patients who had nucleolin-high PDAs compared with 19.5 +/- 3.3 months for patients whose tumors were nucleolin-low (P = 0.03, log-rank method). No significant correlation between nucleolin expression and other clinicopathologic parameters was found. In multivariate analysis, nucleolin expression was a prognostic factor for overall survival in patients with stage II PDA independent of patient's age, gender, tumor size, differentiation, and lymph node status. CONCLUSIONS: Nucleolin was overexpressed in PDAs and PDA cell lines. A high level of nucleolar expression of nucleolin was an independent prognostic marker for better survival for patients with stage II PDAs.

Even low-level HER2 expression may be associated with worse outcome in node-positive breast cancer.

HER2 is an important predictive marker for response to trastuzumab and lapatinib in breast cancer. It is also a powerful prognostic marker in node-positive patients. Although standardized assays are used to help select patients for anti-HER2 therapy, there are no standardized criteria for assessing HER2 as a prognostic marker. Recent data using quantitative image analysis suggest that both high and low HER2 expression are associated with poor clinical outcome. Using the immunohistochemical scoring criteria currently recommended by the College of American Pathologists and American Society of Clinical Oncology to help select patients for trastuzumab, we evaluated HER2 protein expression in tumor tissue microarrays of 91 node-positive patients with invasive breast carcinoma treated with mastectomy and doxorubicin-based chemotherapy without trastuzumab and without irradiation with a median follow-up of 12.5 years. A wide range of HER2 expression (HER2 >or=1+) in the primary tumor was significantly associated with decreased locoregional recurrence-free survival (P=0.014), decreased disease-specific survival (P=0.001), and decreased overall survival (P=0.001). Even in the subset considered HER2 negative by current College of American Pathologists and American Society of Clinical Oncology guidelines, HER2=1+ was associated with worse outcome than HER2=0 in this patient cohort. The association between HER2 >or=1+ and worse outcome had the greatest statistical significance in the hormone receptor-positive subset of patients. These findings support the hypothesis that low-level HER2 expression may have significant clinical implications. Although the assessment of HER2 expression is most important for predicting response to anti-HER2 therapy, detection of low-level HER2 expression might also be useful in helping to select a more aggressive treatment regimen for patients ineligible for anti-HER2 therapy.

Coexpression of alpha6beta4 integrin and guanine nucleotide exchange factor Net1 identifies node-positive breast cancer patients at high risk for distant metastasis.

Preclinical data indicate that alpha6beta4 integrin signaling through Ras homolog gene family, member A, plays an important role in tumor cell motility. The objective of this study was to determine whether the combined expression of alpha6beta4 integrin and neuroepithelioma transforming gene 1 (Net1), a guanine nucleotide exchange factor specific for Ras homolog gene family member A, is associated with adverse clinical outcome in breast cancer patients. Immunohistochemical expression of each protein was evaluated in a tumor tissue microarray prepared from the primary tumors of 94 node-positive patients with invasive breast carcinoma treated with total mastectomy and doxorubicin-based chemotherapy without radiation with a median follow-up of 12.5 years. Associations between staining results and multiple clinicopathologic variables were investigated. Although there was no significant association between alpha6beta4 integrin or Net1 expression and clinical outcome when each marker was considered individually, coexpression of alpha6beta4 and Net1 was associated with decreased distant metastasis-free survival (P = 0.030). In the subset of patients with hormone receptor-positive tumors, coexpression of alpha6beta4 and Net1 was associated with a decrease in distant metastasis-free and overall survival (P < 0.001 and P = 0.006, respectively). Although an association between human epidermal growth factor receptor 2 expression and coexpression of alpha6beta4 and Net1 (P = 0.008) was observed, coexpression of alpha6beta4 and Net1 (hazard ratio, 1.63; P = 0.02) and lymphovascular invasion (hazard ratio, 2.35; P = 0.02) were the only factors independently associated with the development of distant metastasis in multivariate analysis. These findings suggest that coexpression of alpha6beta4 integrin and Net1 could be a useful biomarker for aggressive disease in node-positive breast cancer patients.

Polypyrimidine tract binding protein and Notch1 are independently re-expressed in glioma.

Polypyrimidine tract binding protein (PTB) is expressed in developing mammalian astrocytes, absent in mature adult astrocytes, and aberrantly elevated in gliomas. It is unclear whether PTB is a coincidental marker of tumor progression or a significant mediator of tumorigenesis. In developing Drosophila, the absence of the PTB homolog, hephaestus, results in increased Notch activity. Since Notch is a well-known inducer of glial cell fate, we determined whether overexpression of PTB in glial cell tumors provides a selective growth advantage by inhibiting activated Notch (Notch1IC)-mediated differentiation. To do this, we performed an immunohistochemical analysis for expression of PTB, activated Notch1 (Notch1IC), Hes1 (a Notch target), and GFAP on an extensive human tissue microarray that included 246 gliomas, 10 gliosarcomas, and 10 normal brains. Statistically significant PTB overexpression was seen in all glioma grades, with the highest increase in grade IV tumors. Notch1IC was also abnormally expressed in gliomas except in a subset of grade IV tumors in which it was absent. This decrease in Notch1IC was not associated with increased PTB expression. We conclude that PTB, and Notch1 serve as independent and functionally unlinked markers of glioma progression.