Publications by authors named "Venkat R Katkoori"

Background And Aims: Cancer and atherosclerosis share common risk factors and inflammatory pathways that promote their proliferation via vascular endothelial growth factor (VEGF). Because CCs cause mechanical injury and inflammation in atherosclerosis, we investigated their presence in solid cancers and their activation of IL-1β, VEGF, CD44, and Ubiquityl-Histone H2B (Ub-H2B), that promote cancer growth.

Methods: Tumor specimens from eleven different types of human cancers and atherosclerotic plaques were assessed for CCs, free cholesterol content and IL1-β by microscopy, immunohistochemistry, and biochemical analysis.

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Background: The codon 72 polymorphism in p53 has been implicated in colorectal cancer (CRC) risk, prognosis and CRC health disparities. We examined the functional consequence of this polymorphism in CRC.

Experimental Design: Plasmids (pCMV6) that express different phenotypes of p53 [p53 wild type (wt) at codon 72 (R72), R72 with mutation at codon 273 cysteine (R72), p53 mutation at codon 72 (P72) and P72 with mutation at codon 273 (P72)] were constructed.

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Background: Although loss of heterozygosity (LOH) at chromosome location 18q21 and decreased expression of SMAD4 in invasive colorectal cancers (CRCs) correlate with poor patient survival, the prognostic value of LOH at 18q21 and sub-cellular localization of SMAD4 have not been evaluated in relation to tumor stage.

Methods: Genomic DNA samples from 209 formalin-fixed, paraffin-embedded sporadic CRC tissues and their matching controls were analyzed for 18q21 LOH, and corresponding tissue sections were evaluated by immunohistochemistry for expression of SMAD4 and assessed for its sub-cellular localization (nuclear vs. cytoplasmic).

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Objective: To investigate the clinical value of p53 codon 72 single nucleotide polymorphisms (SNPs) and variants of adenomatous polyposis coli (APC) in hepatocellular carcinomas (HCCs).

Methods: DNA and RNA from 51 HCCs and their matching, uninvolved liver tissues were analyzed for p53 mutations, and the methylation and expression of APC variants were determined. Proliferation of each HCC was assessed by Ki67 immunohistochemistry.

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The Nef-M1 peptide competes effectively with the natural ligand of CXC chemokine receptor 4 (CXCR4), stromal cell-derived factor 1-alpha, to induce apoptosis and inhibit growth in colon cancer (CRC) and breast cancer (BC). Its role in tumor angiogenesis, and epithelial-to-mesenchymal transition (EMT) regulation, key steps involved in tumor growth and metastasis, are unknown. We evaluated the angioinhibitory effect of Nef-M1 peptide and examined its role in the inhibition of EMT in these cancers.

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For the rabphillin-3A-like (RPH3AL) gene, a putative tumor suppressor, the clinical significance of genetic alterations in breast cancers was evaluated. DNA and RNA were extracted from formalin-fixed, paraffin-embedded (FFPE) cancers and matching normal tissues. DNA samples were assessed for loss of heterozygosity (LOH) at the 17p13.

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Purpose: MicroRNAs (miRNA) have potential prognostic value for colorectal cancers; however, their value based on patient race/ethnicity and pathologic stage has not been determined. The goal was to ascertain the prognostic value of 5 miRNAs with increased expression in colorectal cancers of African American (black) and non-Hispanic Caucasian (white) patients.

Experimental Design: TaqMan quantitative real-time PCR was used to quantify expression of miR-20a, miR-21, miR-106a, miR-181b, and miR-203 in paired normal and tumor colorectal cancer archival tissues collected from 106 black and 239 white patients.

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Background: Low socioeconomic status (SES) has been associated with abnormal expression of p53 in breast cancer, but this relationship has not been evaluated for colorectal cancer (CRC). A cohort of CRC patients was evaluated to determine if SES is associated with abnormal p53 expression.

Methods: The study population consisted of 249 patients who underwent curative or palliative resections for CRCs at the University of Alabama at Birmingham Hospital.

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Although the prognostic value of p53 abnormalities in Stage III microsatellite stable (MSS) colorectal cancers (CRCs) is known, the gene expression profiles specific to the p53 status in the MSS background are not known. Therefore, the current investigation has focused on identification and validation of the gene expression profiles associated with p53 mutant phenotypes in MSS Stage III CRCs. Genomic DNA extracted from 135 formalin-fixed paraffin-embedded tissues, was analyzed for microsatellite instability (MSI) and p53 mutations.

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MicroRNAs (miRNAs) have prognostic and therapeutic value for colorectal cancers RCs). Although formalin-fixed paraffin-embedded (FFPE) tissues are available for biomarker studies, the stability of miRNAs in these tissues stored for long periods (more than 20 years) is unknown. The present effort involved analysis of 345 FFPE CRC tissues, stored for 6 to 28 years (1982-2004), for the expression of six miRNAs (miR-20a, miR-21, miR-106a, miR-181b, miR-203, and miR-324-5p) using TaqMan(r) microRNA assays and quantitative real-time PCR (qRT-PCR).

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A variety of genetic and molecular alterations underlie the development and progression of colorectal neoplasia (CRN). Most of these cancers arise sporadically due to multiple somatic mutations and genetic instability. Genetic instability includes chromosomal instability (CIN) and microsatellite instability (MSI), which is observed in most hereditary non-polyposis colon cancers (HNPCCs) and accounts for a small proportion of sporadic CRN.

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Article Synopsis
  • A study involving 490 colon cancer patients explored the impact of the number of lymph nodes (LNs) examined on the staging and outcomes for Stage II and III patients.
  • The findings revealed that examining at least 12 LNs did not significantly correlate with patient recurrence or mortality, but examining 20 or more LNs was associated with a reduced risk of mortality and recurrence for Stage II patients.
  • The research suggested that while the traditional 12 LN threshold is not necessary, examining at least 6 LNs is sufficient for adequate staging in these patients.
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A combination tapered fiber-optic biosensor (CTFOB) dip probe for rapid and cost-effective quantification of proteins in serum samples has been developed. This device relies on diode laser excitation and a charged-coupled device spectrometer and functions on a technique of sandwich immunoassay. As a proof of principle, this technique was applied in a quantitative estimation of interleukin IL-6.

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Article Synopsis
  • The study aimed to determine how the expression of apoptotic molecules (Bax, Bcl-2, and p53) could predict the effectiveness of 5-fluorouracil (5-FU) therapy in treating colorectal adenocarcinomas (CRCs).
  • Researchers analyzed tissue samples from 56 CRC patients who received 5-FU treatment post-surgery and 56 matched patients who had surgery only, focusing on the expression levels of the apoptotic markers and overall survival rates.
  • Results indicated that high Bax expression correlates with lower mortality in patients who had surgery without chemotherapy, while a low Bax/Bcl-2 ratio suggests that 5-FU treatment may be more beneficial for some patients, highlighting
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miRNAs serve as micromanagers, negatively regulating gene expression. Since altered miRNA expression is implicated in the pathobiology of various cancers, including colorectal cancers (CRCs), these molecules serve as potential therapeutic targets. Manipulation of miRNAs may offer an alternative therapy for chemo- and radio-resistant CRCs.

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Background: Mucin 4 (MUC4) is aberrantly expressed in colorectal adenocarcinomas (CRCs) but its prognostic value is unknown.

Methods: Archival tissue specimens collected from 132 CRC patients who underwent surgical resection without presurgery or postsurgery therapy were evaluated for expression of MUC4 by using a mouse monoclonal antibody and horseradish peroxidase. MUC4 expression levels were correlated with clinicopathologic features and patient survival.

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Purpose: Several studies have examined the prognostic value of the codon 72 polymorphism of the p53 gene in colorectal adenocarcinoma, but none have addressed patient race/ethnicity. Therefore, this study assessed the prognostic value of this polymorphism in African American and Caucasian colorectal adenocarcinoma patients separately.

Experimental Design: Colorectal adenocarcinomas from 137 African Americans and 236 non-Hispanic Caucasians were assessed for p53 mutations and genotyped for the codon 72 polymorphism.

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For subsets of colorectal adenocarcinoma (CRC) patients, nuclear accumulation of p53 (p53(nac)) and Bcl-2 expression are prognostic indicators. To understand their role in the progression of CRC we evaluated 90 CRCs and their contiguous adenomatous components (CAdCs) for immunohistochemical expression of these markers. In general, p53(nac) and Bcl-2 expression was significantly increased when comparing normal colonic epithelia to CAdCs and CRCs.

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The recently identified human ortholog of the Rabphillin-3A-Like (RPH3AL) gene, located at the 17p13.3 locus, has been assessed for its mutational status and clinical significance in colorectal adenocarcinoma (CRC). Prospectively collected 95 frozen CRCs and their matching benign colonic epithelial tissues were evaluated for mutations and mRNA expression.

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Background: Methionine, an essential amino acid, is important for normal growth and development, as it is required for both protein and polyamine synthesis as well as in methylation reactions. It has been reported that high concentrations of methionine inhibit cellular growth and gene expression in the human breast tumor-derived MCF-7 cells. These effects are thought to be mediated by the modulation of p53.

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Background: Although a majority of studies in cancer biomarker discovery claim to use proportional hazards regression (PHREG) to the study the ability of a biomarker to predict survival, few studies use the predicted probabilities obtained from the model to test the quality of the model. In this paper, we compared the quality of predictions by a PHREG model to that of a linear discriminant analysis (LDA) in both training and test set settings.

Methods: The PHREG and LDA models were built on a 491 colorectal cancer (CRC) patient dataset comprised of demographic and clinicopathologic variables, and phenotypic expression of p53 and Bcl-2.

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Although decreased or lack of expression of Bcl-2 has been correlated with advanced tumor stage and shortened patient survival in colorectal cancer (CRC), its value in predicting the recurrence has not been well explored. Therefore, we assessed the usefulness of phenotypic expression of Bcl-2 in non-Hispanic Caucasian patients with CRCs in identifying risk of recurrence. Archival tissues of 92 Stage II and 66 Stage III primary CRCs were evaluated for immunohistochemical expression of Bcl-2.

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