Near real time confocal microscopy of Ex Vivo cervical tissue: detection of dysplasia

textRecent studies have shown the ability of confocal microscopy to noninvasively image cells in vivo in real time. This ability to visualize nuclei in vivo shows the potential of confocal microscopy to dramatically improve the prevention, detection and therapy of epithelial cancers. More exciting is the potential to quantitatively measure nuclear morphometry providing a basis to automate the cancer detection process. This dissertation describes studies exploring this potential in ex vivo cervical tissue using acetic acid as a nuclear contrast agent. First the use of acetic acid was demonstrated to improved contrast in confocal images of cervical tissue sufficiently to allow segmentation. Segmentation is robust throughout the epithelium in most normal tissue and upper portions of tissue diagnosed with severe dysplasia. Based upon this segmentation, quantitative feature measurements were extracted from confocal images of cervical tissue in a pilot study to determine if the features would aide in the detection of dysplasia. Simultaneously, a qualitative review of confocal images was performed by untrained reviewers and compared with clinical colposcopic impressions, the standard clinical tool aiding in dysplasia detection. The sensitivity and specificity of both the qualitative (95% and 69%) and quantitative (100% and 91%) review were improved compared to colposcopic review (91% and 62%). Finally the ability of confocal microscopy to produce 3D images was explored as a further means to improve dysplasia detection. Based upon Beer’s equation for light attenuation, the scattering coefficient was extracted from 3D image sets of ex vivo cervical tissue and compared with histology from the same precancerous lesion. The results suggested a possible correlation between high scattering values and the presence of dysplasia. Quantitative 3D features were also extracted from 3D image sets and correlated with the presence of CIN 2/3. Increased separation between normal and CIN 2/3 biopsies was produced using the 3D features as compared to the 2D. More importantly, when additional information (scattering coefficient) is combined with the 2D features, the ability to distinguish between normal and CIN 2/3 is 100% accurate in this small sample set.Electrical and Computer Engineerin

An investigation into minichromosomal maintenance proteins (MCMs) for the diagnosis of prostate cancer, as a possible alternative to prostate specific antigen (PSA)

The current strategy for the diagnosis of prostate cancer includes serum prostate specific antigen (PSA) measurement. There is however debate into its specificity and sensitivity, so new diagnostic markers are under investigation. Minichromosomal maintenance proteins (MCMs) are potential markers for the diagnosis of neoplasia, as they are involved in cellular replication. The aim of this study is to assess MCM2, 5 and 7 as new diagnostic markers for prostate cancer, to compare the clinical usefulness of PSA and to develop a less invasive technique for diagnosis. PSA specificity was investigated in several human cellular lines, and a clinical study was performed to assess expression in prostatic tissue and blood serum. MCM2, 5 and 7 was investigated by translational and transcriptional means in two prostate cell lines PNT1A and PC-3. In addition, a clinical study was performed to assess the expression of MCM2, 5 and 7 in prostate tissue, urine and blood The results suggest that PSA is not prostate specific, as it is synthesised and secreted by several non-prostatic cell lines. In addition PSA testing does not conclusively indicate neoplastic tissue and serum testing only has 63% sensitivity and 60% specificity in accurately identifying prostate cancer. The in vitro results suggest that the PC-3 cells express less MCM2, 5 and 7 on both the protein and mRNA level compared to the PNT1A cells, suggesting that MCM2, 5 and 7 maybe performing a bigger role than just replication of DNA. The tissue results indicate that there is an increase in MCM2, 5 and 7 epithelial nuclei staining for neoplastic condition compared to BPH. While the clinical study on urine sediment indicates increased MCM2, 5 and 7 staining in prostatic neoplasia compared to BPH and the transcriptional study on MCM5 can identify neoplastic tissue from BPH as 11/12 cancerous patients expressed MCM5 compared to only 3/23 BPH patients. Finally the transcriptional study on the blood samples is inconclusive and need to be repeated These results suggest that serum PSA testing is not ideal for the diagnosis of prostate cancer, that MCM2, 5 and 7 appear to have potential as new diagnostic markers and may aid the histopathologist to allocate Gleason score. Also the MCMs may have potential in the development of a less invasive technique through the use of urine sediment

Applications of Raman micro-spectroscopy for cancer diagnostics

Bladder cancer has the highest recurrence rate of any cancer, and as with most solid organ malignancies, early diagnosis, detection, and treatment are imperative for good clinical outcomes. Cystoscopy is the cornerstone of bladder diagnostics for real-time visualization of the bladder mucosa. However, it is an uncomfortable, invasive procedure, and is not without significant risk and potential complications for the patient. Urine cytology is currently the only non-invasive diagnostic tool available for the diagnosis of bladder cancer; this method is highly sensitive for high grade tumours, but has low sensitivity for low grade tumours, which accounts for the majority of cases. Therefore, there exists a clinical need to develop and integrate a non-invasive, accurate technique to assist in the diagnosis of bladder cancer. The combination of Raman micro-spectroscopy and voided urine cytology may provide an ideal platform to replace cystoscopy for bladder cancer diagnostics. By recording Raman spectra from cells obtained from urine cytology, it is possible to analyse the spectral differences associated with the biomolecular continuum of disease progression, as well as being able to classify between different pathological subgroups. Previous studies to date have shown promising results in the application of Raman based urine cytology; however, there appears a high degree of variability across experimental protocols, which is believed to have hindered the advancement of this technique into the clinic. This thesis involves the design and building of a confocal Raman micro-spectrometer to be utilised for the analysis of urine cytology samples, with a key emphasis on the translation of Raman based urine cytology into the clinic. In order to achieve this, a range of traditional protocols and consumables are systematically examined in terms of their compatibility with Raman micro-spectroscopy, as well as comparing the differences between Raman micro-spectroscopy and another form of vibrational spectroscopy for bladder and prostate cancer diagnostics. Although no patient urine cytology samples are used in this thesis, simulated samples are generated using bladder and prostate cell lines along with commercially available synthetic urine. Additional experimentation is provided in order to investigate the impact of hypoxia and exosomal communication on cellular biochemistry

Development of a cell-based lab-on-a-chip sensor for detection of oral cancer biomarkers

textOral cancer is the sixth most common cancer worldwide and has been marked by high morbidity and poor survival rates that have changed little over the past few decades. Beyond prevention, early detection is the most crucial determinant for successful treatment and survival of cancer. Yet current methodologies for cancer diagnosis based upon pathological examination alone are insufficient for detecting early tumor progression and molecular transformation. Development of new diagnostic tools incorporating tumor biomarkers could enhance early detection by providing molecular-level insight into the biochemical and cellular changes associated with oral carcinogenesis. The work presented in this doctoral dissertation aims to address this clinical need through the development of new automated cellular analysis methods, incorporating lab-on-a-chip sensor techniques, for examination of molecular and morphological biomarkers associated with oral carcinogenesis. Using the epidermal growth factor receptor (EGFR) as a proof-of-principle biomarker, the sensor system demonstrated capacity to support rapid biomarker analysis in less than one-tenth the time of traditional methods and effectively characterized EGFR biomarker over-expression in oral tumor-derived cell lines. Successful extension from in vitro tumor cell lines to clinically relevant exfoliative brush cytology was demonstrated, providing a non-invasive method for sampling abnormal oral epithelium. Incorporation of exfoliative cytology further helped to define the important assay and imaging parameters necessary for dual molecular and morphological analysis in adherent epithelium. Next, this new sensor assay and method was applied in a small pilot study in order to secure an initial understanding of the diagnostic utility of such biosensor systems in clinical settings. Four cellular features were identified as useful indicators of cancerous or pre-cancerous conditions including, the nuclear area and diameter, nuclear-to-cytoplasm ratio, and EGFR biomarker expression. Further examination using linear regression and ROC curve analysis identified the morphological features as the best predictors of disease while a combination of all features may be ideal for classification of OSCC and pre-malignancy with high sensitivity and specificity. Further testing in a larger sample size is necessary to validate this regression model and the LOC sensor technique, but shows strong promise as a new diagnostic tool for early detection of oral cancer.Chemistry and Biochemistr

DNA damage in paediatric obesity: a promoter and predictor of cancer in adulthood

Obesity in children is one of the most serious, global, public health challenges of the 21st century. The accumulation of adipose tissue is associated with a range of metabolic complications including diabetes, cardiovascular disease and dyslipidaemia. Epidemiological evidence links obesity in childhood with developing certain types of cancer later in life. It is postulated that excess adipose tissue and consequent inflammation derived oxidative stress may inflict an accumulation of deleterious DNA mutations and promote genome instability and drive carcinogenesis. Furthermore, a deficiency in micronutrients that are essential for DNA repair may exacerbate this pathological state. This research combined the assessment of anthropometric, inflammatory, micro-nutritional and DNA damage biomarkers via non-invasive techniques. In total, 112 children were recruited from schools and NHS obesity clinics. Anthropometric markers assessed were waist to hip ratio, body fat percentage via bioelectrical impedance, and body mass index standard deviation scores (BMI-SDS). These markers were used to classify participants as obese or nonobese and used for correlational analysis. Inflammation and micronutrient status were determined via C-reactive protein and vitamin D Enzyme Immune Assay (EIA) in saliva. DNA damage assessments include a microscopic assessment of nuclear anomalies via the buccal cytome assay, salivary telomere length via quantitative Polymerase Chain Reaction (qPCR) and urinary 8- hydroxyguanosine (8-OHdG) via EIA. The results from this study indicate obesity to be concurrent with increased inflammation and vitamin D deficiency in this cohort of participants. In addition, obesity was associated with increased oxidative DNA damage (8-OHdG) in urine and DNA damage events in the buccal mucosa. Salivary telomere length was positively correlated with obesity and the total frequency of nuclear anomalies found in buccal epithelial cells. Furthermore, there was a negative correlation between vitamin D and the frequency of nuclear anomalies in the oral cavity. Importantly, odds ratio analysis indicates a high BMI Z-score, waist circumference, body fat percentage, salivary CRP and low salivary vitamin D to be independent risk factors for increased nuclear anomalies in the buccal mucosa. This research is the first to accrue evidence for acquired DNA damage in multiple tissues obtained non-invasively from children with obesity. Our findings instigate that biomonitoring of ‘genome health’ for pre-cancerous molecular and morphological markers in obese patients may inform prioritization and severity of clinical intervention measures to prevent malignancy

Critique of fourier transform infrared microspectroscopy applications to prostate pathology diagnosis

Prostate cancer is a biologically heterogenous disease with considerable variation in clinical aggressiveness. Gleason grade, the universally accepted method for classification of prostate cancer, is subjective and gives limited predictive information regarding prostate cancer progression. There is a clinical need for an objective, reliable tool to help pathologists improve current prostate tissue analysis methods and better assess the malignant potential of prostate tumours. Fourier Transform Infrared (FTIR) microspectroscopy is a powerful bioanalytical technique that uses infrared light to interrogate biological tissue. The studies detailed in this thesis examine the ability of FTIR combined with multivariate analysis to discriminate between benign, premalignant and malignant prostate pathology in snap frozen, paraffinated and deparaffinated tissue. Prostate tissue was collected during and after urological procedures performed between 2005 and 2008. The tissue was analysed utilising a bench top FTIR system in point and image mapping modes. The histology under interrogation was identified by a uro- pathologist. Multivariate analysis was applied to the spectral dataset obtained. FTIR performance was evaluated. FTIR was able to reproducibly discriminate between benign and malignant prostate tissue in a pilot study. Cross validated diagnostic algorithms, constructed from the spectral dataset in this experiment, achieved sensitivities and specificities of 95% and 89% respectively. FTIR analysis of transverse paraffinated and deparaffinated radical prostatectomy sections achieved good differentiation of the benign, premalignant and malignant pathology groups. However the performance of diagnostic algorithms constructed from this dataset under cross validation was poor. The work in this thesis illustrates the potential of FTIR to provide an objective method to assist the pathologist in the assessment of prostate samples. The limitations of the technique and directions for future work are presented.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

An investigation into minichromosomal maintenance proteins (MCMs) for the diagnosis of prostate cancer, as a possible alternative to prostate specific antigen (PSA)

The current strategy for the diagnosis of prostate cancer includes serum prostate specific antigen (PSA) measurement. There is however debate into its specificity and sensitivity, so new diagnostic markers are under investigation. Minichromosomal maintenance proteins (MCMs) are potential markers for the diagnosis of neoplasia, as they are involved in cellular replication. The aim of this study is to assess MCM2, 5 and 7 as new diagnostic markers for prostate cancer, to compare the clinical usefulness of PSA and to develop a less invasive technique for diagnosis. PSA specificity was investigated in several human cellular lines, and a clinical study was performed to assess expression in prostatic tissue and blood serum. MCM2, 5 and 7 was investigated by translational and transcriptional means in two prostate cell lines PNT1A and PC-3. In addition, a clinical study was performed to assess the expression of MCM2, 5 and 7 in prostate tissue, urine and blood The results suggest that PSA is not prostate specific, as it is synthesised and secreted by several non-prostatic cell lines. In addition PSA testing does not conclusively indicate neoplastic tissue and serum testing only has 63% sensitivity and 60% specificity in accurately identifying prostate cancer. The in vitro results suggest that the PC-3 cells express less MCM2, 5 and 7 on both the protein and mRNA level compared to the PNT1A cells, suggesting that MCM2, 5 and 7 maybe performing a bigger role than just replication of DNA. The tissue results indicate that there is an increase in MCM2, 5 and 7 epithelial nuclei staining for neoplastic condition compared to BPH. While the clinical study on urine sediment indicates increased MCM2, 5 and 7 staining in prostatic neoplasia compared to BPH and the transcriptional study on MCM5 can identify neoplastic tissue from BPH as 11/12 cancerous patients expressed MCM5 compared to only 3/23 BPH patients. Finally the transcriptional study on the blood samples is inconclusive and need to be repeated These results suggest that serum PSA testing is not ideal for the diagnosis of prostate cancer, that MCM2, 5 and 7 appear to have potential as new diagnostic markers and may aid the histopathologist to allocate Gleason score. Also the MCMs may have potential in the development of a less invasive technique through the use of urine sediment.EThOS - Electronic Theses Online ServiceGBUnited Kingdo