Fluid Biomarkers in HPV and Non-HPV Related Oropharyngeal Carcinomas: From Diagnosis and Monitoring to Prognostication-A Systematic Review.

Biomarkers are crucial in oncology, from detection and monitoring to guiding management and predicting treatment outcomes. Histological assessment of tissue biopsies is currently the gold standard for oropharyngeal cancers, but is technically demanding, invasive, and expensive. This systematic review aims to review current markers that are detectable in biofluids, which offer promising non-invasive alternatives in oropharyngeal carcinomas (OPCs). A total of 174 clinical trials from the PubMed search engine in the last 5 years were identified and screened by 4 independent reviewers. From these, 38 eligible clinical trials were found and subsequently reviewed. The biomarkers involved, categorized by human papillomavirus (HPV)-status, were further divided according to molecular and cellular levels. Recent trials investigating biomarkers for both HPV-positive and HPV-negative OPCs have approaches from various levels and different biofluids including plasma, oropharyngeal swabs, and oral rinse. Promising candidates have been found to aid in detection, staging, and predicting prognosis, in addition to well-established factors including HPV-status, drinking and smoking status. These studies also emphasize the possibility of enhancing prediction results and increasing statistical significance by multivariate analyses. Liquid biopsies offer promising assistance in enhancing personalized medicine for cancer treatment, from lowering barriers towards early screening, to facilitating de-escalation of treatment. However, further research is needed, and the combination of liquid biopsies with pre-existing methods, including in vivo imaging and invasive techniques such as neck dissections, could also be explored in future trials.

Proteomic analysis of the intestinal adaptation response reveals altered expression of fatty acid binding proteins following massive small bowel resection.

Intestinal adaptation in response to the loss of the small intestine is essential to restore enteral autonomy in patients who have undergone massive small bowel resection (MSBR). In a proportion of patients, intestinal function is not restored, resulting in chronic intestinal failure (IF). Early referral of such patients for transplant provides the best prognosis; however, the molecular mechanisms underlying intestinal adaptation remain elusive and there is currently no convenient marker to predict whether patients will develop IF. We have investigated the adaptation response in a well-characterized porcine model of intestinal adaptation. 2D DIGE analysis of ileal epithelium from piglets recovering from massive small bowel resection (MSBR) identified over 60 proteins that changed specifically in MSBR animals relative to nonoperational or sham-operated controls. Three fatty acid binding proteins (L-FABP, FABP-6, and I-FABP) showed changes in MSBR animals. The expression changes and localization of each FABP were validated by immunoblotting and immunohistochemical analysis. FABP expression changes in MSBR animals occurred concurrently with altered triglyceride and bile acid metabolism as well as weight gain. The observed FABP expression changes in the ileal epithelium occur as part of the intestinal adaptation response and could provide a clinically useful marker to evaluate adaptation following MSBR.

Post-translational modifications and protein-specific isoforms in endometriosis revealed by 2D DIGE.

Endometriosis is a chronic disorder affecting approximately 10% of women in whom endometrial tissue forms painful lesions outside the uterus. It has a major impact on their physical, mental and social well-being but has no known cure, and there is no nonsurgical means of diagnosis. We have used a proteomic approach to identify proteins with altered abundance in the eutopic endometrium of endometriosis patients in the midsecretory phase of the menstrual cycle. 2D-differential in gel electrophoresis (DIGE) and mass spectrometry identified 20 proteins that were present at different levels in endometriosis patients (p < 0.05), many of which have not previously been associated with endometriosis. Protein abundance changes did not correlate well with published gene array data, emphasizing the extensive post-translational modification that occurs in this tissue. Abundance or localization changes in endometrial tissue were validated by immunohistochemistry and Western blotting for three proteins, vimentin (VIM), peroxiredoxin 6 (PRDX6), and ribonuclease/angiogenin inhibitor 1 (RNH1), while observed changes could not be confirmed for coronin 1A (CORO1A) or transgelin (TAGLN2). In addition, multiple charge and size isoforms were observed for PDRX6 and vimentin (VIM), and an additional PDRX6 isoform was observed in endometriosis patients that was below the level of detection in healthy women. Biological pathway analysis identified that cytoskeletal remodeling via keratin intermediate filaments, processing of the cystic fibrosis transmembrane receptor (CFTR), the glucocorticoid receptor subunit alpha (GCR), and heat shock factor 1 (HSF1) were all significantly over-represented features in endometriosis patients. This study highlights the highly dynamic nature of endometrial tissue and suggests that considerable post-translational modification of proteins is a key factor in the pathology of endometriosis.

Proteomics and the search for biomarkers of female reproductive diseases.

Over the past decade, high-throughput proteomics technologies have evolved considerably and have become increasingly more commonly applied to the investigation of female reproductive diseases. Proteomic approaches facilitate the identification of new disease biomarkers by comparing the abundance of hundreds of proteins simultaneously to find those specific to a particular clinical condition. Some of the best studied areas of female reproductive biology applying proteomics include gynaecological cancers, endometriosis and endometrial infertility. This review will discuss the progress that has been made in these areas and will highlight some of the emerging technologies that promise to contribute to better understanding of the female reproductive disease.

Androgens and androgen receptor in prostate and ovarian malignancies.

The molecular and biochemical mechanisms contributing to the development and progression of both prostate and ovarian carcinogenesis are currently unknown. A better understanding of the cross-talk between endocrine, signal transduction and regulatory pathways in normal and neoplastic prostatic and ovarian tissues is necessary to elucidate malignant progression in these tissues. This review compares these two malignancies with reference to androgens and the androgen receptor. In particular, the expression and relevance of androgen-regulated genes are discussed. Cytokines, co-activators and co-regulators that interact or effect the androgen receptor are also considered. With increased understanding of the molecular mechanisms of prostate and ovarian carcinogenesis, the identification and development of novel and existing biomarkers may become more achievable.

Quantitative profiling of LNCaP prostate cancer cells using isotope-coded affinity tags and mass spectrometry.

Androgens are involved in the pathogenesis of diseases including adenocarcinoma of the prostate. These hormones are important for growth, maintenance, and integrity of structure and function of the prostate. Androgen-deprivation is currently the only effective systemic therapy for prostate cancer but the effects of androgens on the proteome are still poorly described. Here we quantitatively profile changes in the proteome of LNCaP human prostate cancer cells in response to androgen using the newly developed isotope-coded affinity tag (ICAT) labeling and two-dimensional liquid chromatography-tandem mass spectroscopy (2-D LC-MS/MS). ICAT enables the concurrent identification and comparative quantitative analysis of proteins present in various biological samples including human cell and tissue extracts. Quantification and identification of 139 proteins in complex protein mixtures obtained from androgen-stimulated and unstimulated LNCaP cells were achieved. Changes in levels of 77 proteins in response to androgens were detected. Some of these proteins have been previously reported to be regulated by androgens and include spermine synthase, fatty acid synthase and calreticulin precursor. A large number of proteins that have not been previously reported to be expressed in prostate cells were also quantitatively identified. Examples of these include members of the dual specificity protein phosphatase subfamily, "similar" to hypothetical protein DKFZp434B0328.1, "similar" to 14-3-3 protein zeta and "similar" to hypothetical protein 458, components of the actin cytoskeleton and a range of unknown/uncharacterized proteins. This catalogue of proteins provides an overview of the proteome of prostate cancer cells and the global changes that occur in response to androgens.

Purification of the keratan sulfate proteoglycan expressed in prostatic secretory cells and its identification as lumican.

BACKGROUND: Secretory epithelial cells of human prostate contain a keratan sulfate proteoglycan (KSPG) associated with the prostatic secretory granules (PSGs). The proteoglycan has not been identified, but like the PSGs, it is lost in the early stages of malignant transformation. METHODS: Anion exchange and affinity chromatography were used to purify KSPG from human prostate tissue. Enzymatic deglycosylation was used to remove keratan sulfate (KS). The core protein was isolated using 2D gel electrophoresis, digested in-gel with trypsin, and identified by peptide mass fingerprinting (PMF). RESULTS: The purified proteoglycan was detected as a broad smear on Western blots with an apparent molecular weight of 65-95 kDa. The KS moiety was susceptible to digestion with keratanase II and peptide N-glycosidase F defining it as highly sulfated and N-linked to the core protein. The core protein was identified, following deglycosylation and PMF, as lumican and subsequently confirmed by Western blotting using an anti-lumican antibody. CONCLUSIONS: The KSPG associated with PSGs in normal prostate epithelium is lumican. While the role of lumican in extracellular matrix is well established, its function in the prostate secretory process is not known. It's potential to facilitate packaging of polyamines in PSGs, to act as a tumor suppressor and to mark the early stages of malignant transformation warrant further investigation.

Proteomic analysis of normal and malignant prostate tissue to identify novel proteins lost in cancer.

BACKGROUND: Alterations of important protein pathways, including loss of prostate secretory granules, and disruption of the prostatic secretory pathway have been identified as early events in malignancy. In this study, proteomics was used to map the differences in protein expression between normal and malignant prostate tissues and to identify and analyze differentially expressed proteins in human prostate tissue with particular regard to the proteins lost in malignancy. METHODS: Small quantities of normal and malignant prostate tissue were taken fresh from 34 radical prostatectomy cases. After histological examination, proteins were solubilized from selected tissues and separated using two-dimensional electrophoresis. Using image analysis, the proteome of normal and malignant tissues were mapped and differentially expressed proteins (present in normal and absent in malignant tissue) were identified and subsequently analyzed using peptide mass finger printing and N-terminal sequencing. Western blotting and immunohistochemistry were performed to examine expression profiles and tissue localization of candidate proteins. RESULTS: Comparison of protein maps of normal and malignant prostate were used to identify 20 proteins which were lost in malignant transformation, including prostate specific antigen (PSA), alpha-1 antichymotrypsin (ACT), haptoglobin, and lactoylglutathione lyase. Three of the 20 had not previously been reported in human prostate tissue (Ubiquitin-like NEDD8, calponin, and a follistatin-related protein). Western blotting confirmed differences in the expression profiles of NEDD8 and calponin, and immunohistochemistry demonstrated differences in the cellular localization of these two proteins in normal and malignant prostate glands. CONCLUSIONS: The expression of NEDD8, calponin, and the follistatin-related protein in normal prostate tissues is a novel finding and the role of these important functional proteins in normal prostate and their loss or reduced expression in prostate malignancy warrants further investigations.