Heterogeneity, histological features and DNA ploidy in oral carcinoma by image-based analysis

Predicting progression of low-grade oral dysplasia using brushing based DNA ploidy and Chromatin Organization analysis

Most oral cancers arise from oral potentially malignant lesions, which show varying grades of dysplasia. Risk of progression increases with increasing grade of dysplasia, however risk prediction among oral low-grade dysplasia (LGDs) i.e., mild and moderate dysplasia can be challenging as only 5-15% transform. Moreover, grading of dysplasia is subjective and varies with the area of the lesion being biopsied. To date, no biomarkers or tools are used clinically to triage oral LGDs. This study utilizes a combination of DNA ploidy and chromatin organization (CO) scores from cells obtained from lesion brushings to identify oral LGDs at high-risk of progression. A total of 130 lesion brushings from patients with oral LGDs were selected of which 16 (12.3%) lesions progressed to severe dysplasia or cancer. DNA ploidy and CO scores were analyzed from nuclear features measured by our in-house DNA image cytometry (DNA-ICM) system and used to classify brushings into low risk and high risk. A total of 57 samples were classified as high-risk of which 13 were progressors. High-risk DNA brushing was significant for progression (P = 0.001) and grade of dysplasia (P = 0.004). Multivariate analysis showed high-risk DNA brushing showed 5.1 to 8-fold increased risk of progression, a stronger predictor than dysplasia grading and lesion clinical features. DNA-ICM can serve as a non-invasive, high throughput tool to identify high-risk lesions several years prior to transformation. This will help clinicians focus on such lesions while low-risk lesions may be spared from unnecessary biopsies.

Clinicopathologic breast cancer characteristics: predictions using global textural features of the ipsilateral breast mammogram

Radiomic features from mammograms have been shown to predict breast cancer (BC) risk; however, their contribution to BC characteristics has not yet been explored. This study included 184 women with BC between January 2012 and April 2017. A set of 33 global radiomic features were extracted from the ipsilateral breast mammogram. Associations between radiomic features and BC characteristics were investigated by univariate logistic regression analysis, and receiver-operating characteristic curve analysis was employed to evaluate the predictive performance of radiomic features. Histogram-based features (mean, 70th percentile, and 30th percentile) weakly differentiated progesterone status and tumor size (AUC range: 0.627-0.652, p ≤ 0.007). One gray level run length matrix (GLRLM)-based feature achieved an AUC of 0.68 in discriminating lymph-node status, and the fractal dimension achieved an AUC of 0.65 in predicting tumor size. After stratifying by age at BC diagnosis and baseline percent density (PD), the average predictive performance of the abovementioned features improved from 0.652 to 0.707 for baseline PD adjustment, and from 0.652 to 0.674 for age at BC diagnosis. Higher predictive performances were found for GLRLM-based features in predicting lymph-node status among younger women with high baseline PD (AUC range: 0.710-0.863), and for fractal features in predicting tumor size among patients with low PD (AUC: 0.704). Global radiomic features from the ipsilateral breast mammogram can predict lymph-node status and tumor size among certain categories of women and should be considered as a non-invasive tool for clinical decision-making in BC-affected women and for forecasting disease progression.

Cell-Proliferation Imaging for Monitoring Response to CDK4/6 Inhibition Combined with Endocrine-Therapy in Breast Cancer: Comparison of [18F]FLT and [18F]ISO-1 PET/CT

PURPOSE

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in combination with endocrine-therapy have emerged as an important regimen of care for estrogen receptor (ER)-positive metastatic breast cancer, although identifying predictive biomarkers remains a challenge. We assessed the ability of two PET-proliferation tracers, [¹⁸F]FLT and [¹⁸F]ISO-1, for evaluating response to CDK4/6-inhibitor (palbociclib) and ER-antagonist (fulvestrant).

EXPERIMENTAL DESIGN

To determine the effect of CDK4/6 inhibition combined with estrogen-blockade, we assessed cell proliferation in six breast cancer cell lines after 1, 3, and 6 days of treatment with palbociclib and/or fulvestrant. These data were correlated to in vitro radiotracer assays and results were verified by longitudinal [¹⁸F]FLT and [¹⁸F]ISO-1 micro-PET imaging performed in MCF7 tumor-bearing mice.

RESULTS

All palbociclib-sensitive cell lines showed decreased [¹⁸F]FLT accumulation and S-phase depletion after treatment, with both measures augmented by combination therapy. In contrast, these cells showed changes in [¹⁸F]ISO-1 analogue-binding and G₀ arrest only after prolonged treatment. MicroPET imaging of MCF7 xenografts showed a significant decrease in [¹⁸F]FLT but no changes in [¹⁸F]ISO-1 uptake in all treated mice on day 3. On day 14, however, mice treated with combination therapy showed a significant decrease in [¹⁸F]ISO-1, corresponding to G₀ arrest, while maintaining reduced [¹⁸F]FLT uptake, which corresponded to S-phase depletion.

CONCLUSIONS

Our data suggest complementary roles of [¹⁸F]FLT and [¹⁸F]ISO-1 PET in evaluating tumor-proliferation after combined CDK4/6 inhibitor and endocrine therapy in breast cancer. [¹⁸F]FLT is more sensitive to immediate changes in S-phase, whereas [¹⁸F]ISO-1 can assess more delayed changes related to cell-cycle arrest and transition to G₀ quiescence from combination therapy. These data suggest a potential role for early prediction of long-term response using these imaging biomarkers.

Biomarkers: paving stones on the road towards the personalized precision medicine for oral squamous cell carcinoma

Traditional therapeutics have encountered a bottleneck caused by diagnosis delay and subjective and unreliable assessment. Biomarkers can overcome this bottleneck and guide us toward personalized precision medicine for oral squamous cell carcinoma. To achieve this, it is important to efficiently and accurately screen out specific biomarkers from among the huge number of molecules. Progress in omics-based high-throughput technology has laid a solid foundation for biomarker discovery. With credible and systemic biomarker models, more precise and personalized diagnosis and assessment would be achieved and patients would be more likely to be cured and have a higher quality of life. However, this is not straightforward owing to the complexity of molecules involved in tumorigenesis. In this context, there is a need to focus on tumor heterogeneity and homogeneity, which are discussed in detail. In this review, we aim to provide an understanding of biomarker discovery and application for precision medicine of oral squamous cell carcinoma, and have a strong belief that biomarker will pave the road toward future precision medicine.

An MRI-based Radiomics Classifier for Preoperative Prediction of Ki-67 Status in Breast Cancer

RATIONALE AND OBJECTIVES

This study aims to investigate the value of a magnetic resonance imaging-based radiomics classifier for preoperatively predicting the Ki-67 status in patients with breast cancer.

MATERIALS AND METHODS

We chronologically divided 318 patients with clinicopathologically confirmed breast cancer into a training dataset (n = 200) and a validation dataset (n = 118). Radiomics features were extracted from T2-weighted (T2W) and contrast-enhanced T1-weighted (T1+C) images of breast cancer. Radiomics feature selection and radiomics classifiers were generated using the least absolute shrinkage and selection operator regression analysis method. The correlation between the radiomics classifiers and the Ki-67 status in patients with breast cancer was explored. The predictive performances of the radiomics classifiers for the Ki-67 status were evaluated with receiver operating characteristic curves in the training dataset and validated in the validation dataset.

RESULTS

Through the radiomics feature selection, 16 and 14 features based on T2W and T1+C images, respectively, were selected to constitute the radiomics classifiers. The radiomics classifier based on T2W images was significantly correlated with the Ki-67 status in both the training and the validation datasets (both P < .0001). The radiomics classifier based on T1+C images was significantly correlated with the Ki-67 status in the training dataset (P < .0001) but not in the validation dataset (P = .083). The T2W image-based radiomics classifier exhibited good discrimination for Ki-67 status, with areas under the receiver operating characteristic curves of 0.762 (95% confidence interval: 0.685, 0.838) and 0.740 (95% confidence interval: 0.645, 0.836) in the training and validation datasets, respectively.

CONCLUSIONS

The T2W image-based radiomics classifier was a significant predictor of Ki-67 status in patients with breast cancer. Thus, it may serve as a noninvasive approach to facilitate the preoperative prediction of Ki-67 status in clinical practice.

Image cytometry DNA ploidy analysis: Correlation between two semi-automated methods

BACKGROUND AND OBJECTIVES

Quantitation of cell DNA content, DNA ploidy, has been established as a research and prognostic technique for decades. A variety of instruments have been used although only a few commercially available systems have established quality assurance and published outcome data. The aim of this study was to compare two automated systems.

METHODS

Nuclear monolayers were obtained from 112 oral biopsies by enzyme digestion and Feulgen staining. These were scanned on both the Fairfield and the Ploidy Work Station (PWS) systems. The overall ploidy diagnosis, number of epithelial nuclei, coefficient of variation (CV) and 5c exceeding rate (5CER) were compared by quantile-quantile plots, t test, Wilcoxon and Spearman's tests.

RESULTS

The PWS system identified more nuclei (p < 0.0001) at a lower CV (p < 0.0001). Using the PWS system, fewer samples were classified as indeterminate. No difference between 5CER was found between systems (p > 0.54). There was complete concordance between the two systems in terms of DNA ploidy diagnosis.

CONCLUSIONS

The PWS system is comparable to the Fairfield system for determination of DNA ploidy and has advantages that may lead to improved performance.

Value of automatic DNA image cytometry for diagnosing lung cancer

The present study aimed to investigate the diagnostic value of automatic DNA image cytometry (DNA-ICM) for diagnosing lung cancer. A total of three different types of samples from 465 cases were included: Bronchoalveolar lavage fluid (BALF), 386 samples; pleural effusion cases, 70 samples; and fine-needle aspiration procedures, 9 samples. Two methods, liquid-based cytology (LBC) and automatic DNA-ICM, were used to assess the samples, and the pathological results of 120/465 cases were reviewed. The results of DNA-ICM were compared with those of LBC and pathology. There were 57 cases of lung cancer without aneuploidy and 49 cases without evidence of malignant tumor, but with the presence of heteroploid cells. The positive diagnostic rate for BALF samples using LBC was significantly higher compared with that for DNA-ICM (P<0.05). No statistically significant difference was observed in the positive diagnostic rate between DNA-ICM and LBC in pleural effusion samples. For DNA-ICM in BALF, pleural effusion and all samples, no statistically significant differences were identified between the positive diagnostic rates of lung squamous carcinoma and lung adenocarcinoma. The positive diagnostic rate of LBC combined with DNA-ICM was not significantly improved. In non-small cell lung cancer (NSCLC) cases, the difference in the maximum value of DNA (DNAmax) was positively correlated with tumor stage (P<0.05), but no significant correlations were observed among DNA max, tumor type and tumor location. In small-cell lung cancer (SCLC) cases, no significant correlations were observed among DNAmax, tumor staging or tumor location. The differences in the DNAmax values of squamous cell carcinoma, adenocarcinoma, SCLC and NSCLC were not statistically significant. In the present study, the area under the receiver operating characteristic curve for LBC (0.936) was significantly greater compared with that for DNA-ICM (0.766) (P<0.05). DNA-ICM has medium diagnostic value in lung cancer, and the DNAmax was positively correlated with tumor stage in NSCLC. DNA-ICM may serve as a supplement to LBC, but it is not recommended as a sole procedure for lung cancer screening.

PanCancer insights from The Cancer Genome Atlas: the pathologist's perspective

The Cancer Genome Atlas (TCGA) represents one of several international consortia dedicated to performing comprehensive genomic and epigenomic analyses of selected tumour types to advance our understanding of disease and provide an open-access resource for worldwide cancer research. Thirty-three tumour types (selected by histology or tissue of origin, to include both common and rare diseases), comprising >11 000 specimens, were subjected to DNA sequencing, copy number and methylation analysis, and transcriptomic, proteomic and histological evaluation. Each cancer type was analysed individually to identify tissue-specific alterations, and make correlations across different molecular platforms. The final dataset was then normalized and combined for the PanCancer Initiative, which seeks to identify commonalities across different cancer types or cells of origin/lineage, or within anatomically or morphologically related groups. An important resource generated along with the rich molecular studies is an extensive digital pathology slide archive, composed of frozen section tissue directly related to the tissues analysed as part of TCGA, and representative formalin-fixed paraffin-embedded, haematoxylin and eosin (H&E)-stained diagnostic slides. These H&E image resources have primarily been used to verify diagnoses and histological subtypes with some limited extraction of standard pathological variables such as mitotic activity, grade, and lymphocytic infiltrates. Largely overlooked is the richness of these scanned images for more sophisticated feature extraction approaches coupled with machine learning, and ultimately correlation with molecular features and clinical endpoints. Here, we document initial attempts to exploit TCGA imaging archives, and describe some of the tools, and the rapidly evolving image analysis/feature extraction landscape. Our hope is to inform, and ultimately inspire and challenge, the pathology and cancer research communities to exploit these imaging resources so that the full potential of this integral platform of TCGA can be used to complement and enhance the insightful integrated analyses from the genomic and epigenomic platforms. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Meta-analysis of the predictive value of DNA aneuploidy in malignant transformation of oral potentially malignant disorders

DNA aneuploidy is an imbalance of chromosomal DNA content that has been highlighted as a predictor of biological behavior and risk of malignant transformation. To date, DNA aneuploidy in oral potentially malignant diseases (OPMD) has been shown to correlate strongly with severe dysplasia and high-risk lesions that appeared non-dysplastic can be identified by ploidy analysis. Nevertheless, the prognostic value of DNA aneuploidy in predicting malignant transformation of OPMD remains to be validated. The aim of this meta-analysis was to assess the role of DNA aneuploidy in predicting malignant transformation in OPMD. The questions addressed were (i) Is DNA aneuploidy a useful marker to predict malignant transformation in OPMD? (ii) Is DNA diploidy a useful negative marker of malignant transformation in OPMD? These questions were addressed using the PECO method. Five studies assessing aneuploidy as a risk marker of malignant change were pooled into the meta-analysis. Aneuploidy was found to be associated with a 3.12-fold increased risk to progress into cancer (RR=3.12, 95% CI 1.86-5.24). Based on the five studies meta-analyzed, "no malignant progression" was more likely to occur in DNA diploid OPMD by 82% when compared to aneuploidy (RR=0.18, 95% CI 0.08-0.41). In conclusion, aneuploidy is a useful marker of malignant transformation in OPMD, although a diploid result should be interpreted with caution.

18F-FDG PET/CT in lung cancer. The added value of quantification

OBJECTIVE

To test a software application for the quantification of metabolic heterogeneity and to evaluate its superiority in relation to visual interpretation. To investigate if a quantitative analysis adds information to the interpretation of ¹⁸F-FDG-PET/CT.

MATERIAL AND METHODS

The study analyzed 215 patients with a ¹⁸F-FDG-PET/CT done for the initial staging of lung cancer between March 2011 and December 2015. The study included 57 (26.5%) women and 158 (73.5%) men, with ages ranging from 34 to 88 years (mean±SD: 67.23±10.04). There were 82 surgical stages (I, II, IIIA), and 133 non-surgical stages (IIIB, IV). The primary tumour was analyzed quantitatively by obtaining the following parameters: SUVmax, metabolic active tumour volume (MATV), total lesion glycolysis (TLG), and the entropy heterogeneity index (ET). Heterogeneity was assessed visually. Death dates and/or the follow-up time were registered, ranging from 0.70 to 67.60 months (mean±SD: 23.20±17.68).

RESULTS

In multivariate analysis, ET emerged as a better predictor of survival than visual analysis of heterogeneity that was not statistically significant. The C-index determination demonstrated that all quantitative parameters were statistically-significant predictors of survival. Cut-offs were obtained in order to compare survival times. A multivariate analysis was performed. In the total population, the best predictor was the TNM stage, but MATV, ET, and male gender were statistically significant and independent predictors of survival. In stages without surgical indication, the best predictor was the TNM stage, but the MATV and male gender were statistically significant and independent predictors of survival. In the surgical stages, ET was the only statistically significant and independent predictor of survival.

CONCLUSIONS

Quantification adds prognostic information to the visual analysis of ¹⁸F-FDG-PET/CT.

DNA ploidy and cell cycle protein expression in oral squamous cell carcinomas with and without lymph node metastases

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most frequently occurring malignant tumour in the oral cavity. OSCC arises because of multiple genetic alterations. Cell cycle aberrations and aneuploidy are reportedly among the main characteristics of cancer cells and are associated with aggressive growth and poor prognosis.

METHODS

The study sample included 47 non-metastasised and 39 metastasised primary OSCC, with matched positive cervical lymph nodes and 17 normal oral mucosa samples. Tissue microarrays (TMAs) were prepared with a minimum of three cores from each case. TMA sections were cut and immunostained with MCM2, Ki-67, geminin and cyclin D1 antibodies. DNA image analysis was performed on the whole tissue section before TMAs were created.

RESULTS

The results revealed that there were no differences in cell cycle protein expression in different areas of the tumours or between the metastatic and non-metastatic carcinomas. None of the cell cycle proteins showed significant differences between the lymph node metastasis and the primary OSCC, except for Ki-67. Geminin/Ki-67 ratio showed significant difference between metastatic and non-metastatic tumours. Aneuploidy was detected in all (100%) cases of OSCC. Similarly, all lymph node samples (39 cases) were aneuploid.

CONCLUSION

The results suggest that although there was dysregulation of cell cycle regulatory proteins, only Ki-67 and the MCM2/Ki-67 and geminin/Ki-67 ratios may have prognostic significance in oral cancer. DNA ploidy alone was not specific and may not be a good tool to evaluate prognosis or metastatic progression in oral cavity carcinomas.

Cohesin subunits, STAG1 and STAG2, and cohesin regulatory factor, PDS5b, in oral squamous cells carcinomas

BACKGROUND

Cohesin complex is responsible for sister chromatid cohesion. STAG1/STAG2 is part of the complex, which is regulated by PDS5B. Alterations in these genes were described in tumors. PDS5B is a negative regulator of cell proliferation. We aimed to assess molecular alterations in these genes in oral squamous cell carcinoma (OSCC) and predict their expression by the expression of 84 cell cycle genes. In addition, we investigated whether pds5b protein expression impacted ki-67 and p53 immunopositivity.

METHODS

We assessed loss of heterozygosity (LOH) at STAG1 and STAG2 loci in 15 OSCC using three polymorphic markers. Associations between the immunoexpression of pds5b and ki-67 and p53 were tested in 62 samples. Differences between transcriptional levels of STAG1, STAG2, and PDS5B between OSCC and normal oral mucosa (NM) were evaluated by qPCR. An 84 cell cycle genes qPCR array was carried with OSCC samples, and STAG1, STAG2, and PDS5B were independently used as response variables in multiple linear regression models.

RESULTS

Loss of heterozygosity in at least one marker was observed in three samples. pds5b, p53, and ki-67 were highly expressed, and no association was found between pds5b immunoexpression and ki-67 or p53 (P > 0.05). OSCC and NM showed similar transcriptional levels of STAG1, STAG2, and PDS5B. STAG1 and CUL3 expression seem to be related (P = 0.004).

CONCLUSIONS

There is LOH at STAG1 and STAG2 loci in OSCC, but OSCC and NM showed similar transcriptional levels of STAG1, STAG2, and PDS5B. pds5b immunoexpression in OSCC was high, but it was not associated with proliferation cell index.

Image-based DNA ploidy analysis aids prediction of malignant transformation in oral lichen planus

OBJECTIVES

To investigate the potential of image-based DNA ploidy analysis to predict malignant transformation in patients with oral lichen planus (OLP).

STUDY DESIGN

DNA ploidy analysis was performed on biopsy samples from 14 patients with OLP who underwent malignant transformation. As controls, 42 OLP lesions showing unusual clinical features suggesting a transformation risk and 68 samples of clinically and histologically typical OLP were included. Cases with dysplasia on initial biopsy were excluded. Eighty fibroepithelial polyps acted as methodologic controls. Epithelial nuclei were isolated from formalin-fixed paraffin embedded biopsy samples and monolayers stained with Feulgen for automated image cytometry to establish DNA content. Ploidy status was correlated to outcome using Kaplan-Meier analysis and log-rank Mantel-Cox tests.

RESULTS

All controls and typical OLP were diploid and none underwent malignant transformation in mean follow-up of 14 years (10-18 years). One unusual OLP developed carcinoma and all were diploid. The 14 patients with transformation developed 21 carcinomas. In the 11 patients who had a prior biopsy, 4 were aneuploid.

CONCLUSIONS

DNA ploidy analysis predicted malignant transformation in more than one third (36.4%) of patients with OLP with a preceding biopsy (n = 11). This premalignant nature could not have been diagnosed clinically or by histologic dysplasia assessment.

Evaluation of brush cytology and DNA image cytometry for the detection of cancer of the oral cavity

BACKGROUND

Cancer of the oral cavity is the sixth most common malignancy reported worldwide. This study was undertaken to evaluate the efficacy of brush cytology and the adjunctive role of DNA image cytometry (ICM) in the diagnosis of oral cancer.

METHOD

Oral brush smears and biopsy were obtained from 100 consecutive patients presenting with suspicious oral lesions. DNA-ICM was performed on 96 cytology smears which had adequate cellularity.

RESULTS

On cytology, 54 cases were benign, 36 were malignant, 6 were suspicious for malignancy, and 4 were inadequate due to scanty cellularity. On histopathologic examination, 49 cases were diagnosed as squamous cell carcinoma and 51 cases as benign. The sensitivity of brush cytology for the detection of cancer was 83.3% and the specificity was 95.8%. The positive and negative predictive values were 95.2% and 85.2%, respectively, with a diagnostic accuracy of 86%. Out of 96 cases analyzed by image analysis to assess DNA ploidy, 33 cases were aneuploid and 63 were diploid. The sensitivity, specificity, positive predictive value, and negative predictive value of DNA-ICM were 68.7%, 100%, 100%, and 76.1%, respectively, giving a diagnostic accuracy of 81%. The combination of cytology and DNA cytometry increased the sensitivity to 92% and specificity to 100%.

CONCLUSION

The study demonstrates the usefulness of DNA-ICM as an adjunct to brush cytology to diagnose oral cancer. It reduces the false negative cases on cytology and also adds to objectivity in cytologically doubtful cases.

Inter- and intra-lesional molecular heterogeneity of oral leukoplakia

OBJECTIVES

Oral leukoplakia (OL) is the most common potentially malignant lesion of the oral cavity, and OL diagnosis is a risk factor for developing subsequent oral squamous cell carcinomas (OSCC). Notably, loss of heterozygosity (LOH) profiles have been validated as risk predictors of malignant transformation of OL. Similar to other solid malignant tumors, OSCC exhibit molecular heterogeneity. However, if and to what extent tumor heterogeneity is present in premalignant lesions of the oral cavity has not been addressed. As LOH analysis is currently being used to stratify OL patients at risk for OSCC development in chemoprevention studies, insight into the issue of molecular heterogeneity of OL is of clinical significance.

MATERIALS AND METHODS

To address this issue, 11 polymorphic microsatellite markers localizing to chromosomes 3, 9, 11 and 17 were used to detect LOH in 28 samples of 14 OL patients, by capillary electrophoresis analysis. These samples were either clinically recurrent lesions, or two anatomically distinct biopsies from the same lesion, or even two different OL lesions located at distinct intraoral sites.

RESULTS

In all but one of the biopsies pairs, distinct LOH patterns were displayed regardless of histopathological grade. These data provide evidence for inter- and intra-lesional molecular heterogeneity in OL.

CONCLUSIONS

On the basis of these findings, molecular heterogeneity needs to be addressed in subsequent studies targeting specific carcinogenic pathways/genes in chemoprevention of malignant transformation of OL.

Chromosome instability predicts the progression of premalignant oral lesions

OBJECTIVES

One of the main problems in reducing the incidence of oral squamous cell carcinoma (OSCC) is the inability to appropriately deal with leukoplakia. Accurately identifying lesions which will progress to malignancy is currently not possible. The present study aims to establish the value of chromosome instability (CI) detection by DNA image cytometry and FISH analysis for prognosis and monitoring of oral leukoplakia.

MATERIALS AND METHODS

For this purpose, we included from our archives 102 oral leukoplakia cases, which had been diagnosed between 1991 and 2008. Patient follow-up data were collected and the histopathological diagnosis was revised. CI assessment was carried out on paraffin-embedded tissue sections using both DNA image cytometry (ICM) and dual target FISH for chromosomes 1 and 7.

RESULTS

16 of 102 Patients developed carcinoma in situ or OSCC. Both detection methods were found to yield prognostic information independent of the histopathological diagnosis. CI was a strong individual marker of progression, with hazard ratios (HRs) of 7.2 and 6.8 for ICM and FISH respectively. Moreover, this approach seems suitable for monitoring lesions over time (especially ICM). Combining histopathology and CI enables subdivision of patients into three risk groups, with different probabilities of malignant progression.

CONCLUSION

CI detection seems a reliable method for risk assessment of oral premalignancies and its application may contribute to a better risk-counselling and appropriate treatment regimen or watchfull-waiting approach of patients.

High throughput image cytometry for detection of suspicious lesions in the oral cavity

The successful management of oral cancer depends upon early detection, which relies heavily on the clinician's ability to discriminate sometimes subtle alterations of the infrequent premalignant lesions from the more common reactive and inflammatory conditions in the oral mucosa. Even among experienced oral specialists this can be challenging, particularly when using new wide field-of-view direct fluorescence visualization devices clinically introduced for the recognition of at-risk tissue. The objective of this study is to examine if quantitative cytometric analysis of oral brushing samples could facilitate the assessment of the risk of visually ambiguous lesions. About 369 cytological samples were collected and analyzed: (1) 148 samples from pathology-proven sites of SCC, carcinoma in situ or severe dysplasia; (2) 77 samples from sites with inflammation, infection, or trauma, and (3) 144 samples from normal sites. These were randomly separated into training and test sets. The best algorithm correctly recognized 92.5% of the normal samples, 89.4% of the abnormal samples, 86.2% of the confounders in the training set as well as 100% of the normal samples, and 94.4% of the abnormal samples in the test set. These data suggest that quantitative cytology could reduce by more than 85% the number of visually suspect lesions requiring further assessment by biopsy.

Correlation between Ki-67 immunohistochemistry and 18F-fluorothymidine uptake in patients with cancer: A systematic review and meta-analysis

BACKGROUND

Positron emission tomography (PET) imaging using the radiotracer 18F-Fluorothymidine (FLT) has been proposed as an imaging biomarker of tumour proliferation. If FLT-PET can be established as such it will provide a non-invasive, quantitative measurement of tumour proliferation across the entire tumour. Results from validation studies have so far been conflicting with some studies confirming a good correlation between FLT uptake and Ki-67 score and others presenting negative results.

METHODS

Firstly we performed a systematic review of published studies between 1998 and 2011 that explored the correlation between FLT uptake and Ki-67 score and examined possible variations in the methods used. Studies were eligible if they: (a) included patients with cancer, (b) investigated the correlation between Ki-67 measured by immunohistochemistry and FLT uptake measured with PET scanning, and (c) were published as a full paper in a peer-reviewed scientific journal. Secondly a meta-analysis of the correlation coefficient values reported from each study was performed. Correlation coefficient (r) values were extracted from each study and 95% confidence intervals (CIs) were calculated after applying Fisher's z transformation. For subgroup analysis, studies were classified by the index used to characterise Ki-67 expression (average or maximum expression), the nature of the sample (whole specimen or biopsy) and the cancer type.

FINDINGS

Twenty-seven studies were identified as eligible for the meta-analysis. In the studies we examined there were variations in aspects of the methods and reporting. The meta-analysis showed that given an appropriate study design the FLT/Ki-67 correlation is significant and independent of cancer type. Specifically subgroup analysis showed that FLT/Ki-67 correlation was high in studies measuring the Ki-67 average expression regardless of use of surgery or biopsy samples (r=0.70, 95% CI=0.43-0.86, p<0.001). Of the studies that measured Ki-67 maximum expression, only those that used the whole surgical specimen provided a significant r value (r=0.72, 95% CI=0.54-0.84, p<0.001). Studies that used biopsy samples for Ki-67 maximum measurements did not produce a significant r value (r=0.04, 95% CI=-0.18-0.26, p=0.71). In terms of the cancer type subgroup analysis there is sufficient data to support a strong FLT/Ki-67 correlation for brain, lung and breast cancer. No publication bias was detected.

INTERPRETATION

This systematic review and meta-analysis highlights the importance of the methods used in validation studies comparing FLT-PET imaging with the biomarker Ki-67. The correlation is significant and independent of cancer type provided a study design that uses Ki-67 average measurements, regardless of nature of sample, or whole surgical samples when measuring Ki-67 maximum expression. Sufficient data to support a strong correlation for brain, lung and breast cancer exist. However, larger, prospective studies with improved study design are warranted to validate these findings for the rest of the cancer types.

Population-based study of DNA image cytometry as screening method for esophageal cancer

AIM: To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esophageal squamous precancerous lesions.

METHODS: This study was designed as a population-based screening study. A total of 582 local residents aged 40 years-69 years were recruited from Linzhou in Henan and Feicheng in Shandong. However, only 452 subjects had results of liquid-based cytology, DNA-ICM and pathology. The sensitivity and specificity of DNA-ICM were calculated and compared with liquid-based cytology in moderate dysplasia or worse.

RESULTS: Sensitivities of DNA-ICM ranging from at least 1 to 4 aneuploid cells were 90.91%, 86.36%, 79.55% and 77.27%, respectively, which were better than that of liquid-based cytology (75%). Specificities of DNA-ICM were 70.83%, 84.07%, 92.65% and 96.81%, but the specificity of liquid-based cytology was 91.91%. The sensitivity and specificity of a combination of liquid-based cytology and DNA-ICM were 84.09% and 85.78%, respectively.

CONCLUSION: It is possible to use DNA-ICM technique as a primary screening method for esophageal squamous precancerous lesions.

Quantifying heterogeneity in human tumours using MRI and PET

Most tumours, even those of the same histological type and grade, demonstrate considerable biological heterogeneity. Variations in genomic subtype, growth factor expression and local microenvironmental factors can result in regional variations within individual tumours. For example, localised variations in tumour cell proliferation, cell death, metabolic activity and vascular structure will be accompanied by variations in oxygenation status, pH and drug delivery that may directly affect therapeutic response. Documenting and quantifying regional heterogeneity within the tumour requires histological or imaging techniques. There is increasing evidence that quantitative imaging biomarkers can be used in vivo to provide important, reproducible and repeatable estimates of tumoural heterogeneity. In this article we review the imaging methods available to provide appropriate biomarkers of tumour structure and function. We also discuss the significant technical issues involved in the quantitative estimation of heterogeneity and the range of descriptive metrics that can be derived. Finally, we have reviewed the existing clinical evidence that heterogeneity metrics provide additional useful information in drug discovery and development and in clinical practice.

Genetics/epigenetics of oral premalignancy: current status and future research

Squamous cell carcinoma (SCC) of the oral and oropharyngeal region is the sixth most common malignancy in the world today. Despite numerous advances in treatment, long-term survival from this disease remains poor. Early detection can decrease both morbidity and mortality associated with this neoplasm. However, screening for potentially malignant disease is typically confounded by difficulty in discriminating between reactive/inflammatory lesions vs those lesions that are premalignant in nature. Furthermore, the histologic diagnosis of dysplasia can be subjective and is thus prone to a considerable range of interpretation. Similarly, no definitive, validated criteria exist for predicting which dysplastic lesions are most likely to progress to cancer over time. Given this state of science, the presence of dysplasia can only be used to indicate that an oral lesion may have an increased risk of malignant transformation. Molecular biomarkers capable of identifying the subset of lesions likely to progress to cancer are required to eliminate this clinical diagnostic dilemma. The purpose of this review is to assess the current state of knowledge regarding genetic/epigenetic alterations observed in oral mucosal premalignancy. In addition, recommendations for future research studies directed at defining the predictive capacity of specific biomarkers in this modeling are presented.

Impact of WWOX alterations on p73, ΔNp73, p53, cell proliferation and DNA ploidy in salivary gland neoplasms

OBJECTIVE

WWOX gene is altered in a variety of neoplasms. Wwox is pro-apoptotic through interaction with p73 and may be involved in chromosomal stability by interaction with p73 and p53. The aims of this study were to characterize WWOX transcription, methylation status and immunoexpression in salivary neoplasms and to determine whether these were associated with p73, p53, cell proliferation and DNA ploidy.

MATERIALS AND METHODS

Seven malignant and 21 benign fresh salivary neoplasms were included. WWOX expression was determined by RT-PCR and sequencing of transcripts, quantitative PCR and immunohistochemistry. Methylation-specific PCR was used to assess the methylation of its first exon. For p73, ΔNp73, p53 and ki67 immunohistochemistry and ploidy analysis, 29 malignant samples from archives were included.

RESULTS

No consistent pattern of WWOX exon 1 methylation was found, but aberrant and novel transcripts were observed in 17/28 neoplasms; 55% of tumours showed reduced WWOX RNA. WWOX RNA levels were associated with p53 immunopositivity. Immunohistochemical Wwox expression did not correlate with methylation status, p53 or p73 expression or proliferation. p73, proliferation and DNA ploidy were associated with malignant phenotype.

CONCLUSION

Aberrant WWOX transcription and decreased expression are frequent in salivary neoplasms and WWOX transcription is associated with p53 staining.

S-phase fraction and DNA ploidy in oral leukoplakia

BACKGROUND

The risk of malignant conversion in oral leukoplakia is well documented. Histological findings are often unreliable and it is difficult to predict on the basis of clinical and histopathological changes which leukoplakic lesion will turn malignant.

METHODS

We used the technique of flow cytometry to evaluate the ploidy status, DNA index and S-phase fraction in leukoplakia, oral cancer and normal oral mucosal biopsies and compared it with histological findings. The study was carried out on 30 patients with oral cancer, 60 with leukoplakia and 30 with normal oral mucosal biopsies.

RESULTS

The aneuploidy rate in oral cancers was 64%, for leukoplakia 20%, while all normal mucosal biopsies were diploid. Aneuploid lesions also had a greater S-phase fraction (SPF). The DNA Index (DI) of aneuploid oral cancers was 1.72 and aneuploid leukoplakias was 1.24. Leukoplakia specimens which showed histological evidence of dysplasia had aneuploidy rate of 38%, DI of 1.19 and SPF of 6.2%. The corresponding values for leukoplakia specimens without dysplasia were 14%, 1.09 and 4.1%, respectively.

CONCLUSION

The method of flow cytometry can be used to identify the subset of leukoplakia patients who are at a higher risk of malignant conversion. These patients could undergo more rigid surveillance or undergo excision biopsy of their lesions.

Abnormal DNA content in oral epithelial dysplasia is associated with increased risk of progression to carcinoma

Background:

Oral epithelial dysplasia (OED) is a histologically detectable lesion that may progress to carcinoma but there are no accurate markers that predict progression. This study examined the development of carcinoma from oral dysplastic lesions, and the association between abnormal DNA content and progression to carcinoma.

Methods:

Epithelial dysplasias from the Oral Pathology Diagnostic Service were matched against the Ontario Cancer Registry database to identify cases that progressed to carcinoma. A case–control study was conducted to compare DNA image cytometry of dysplasias that progressed with those that have not progressed. For a subset of the progressed dysplasias, DNA content of the carcinoma was also analysed.

Results:

A total of 8% of epithelial dysplasias progressed to carcinoma after 6–131 months. In all, 28 of 99 dysplasias showed abnormal DNA content by image cytometry. In multivariate analysis of time to progression, abnormal DNA content was a significant predictor with hazard ratio of 3.3 (95% confidence interval: 1.5–7.4) corrected for site and grade of dysplasia. Analysis of sequential samples of dysplasia and carcinoma suggested that epithelial cell populations with grossly abnormal DNA content were transient intermediates during oral cancer development.

Conclusions:

Abnormal DNA content is a significant biomarker of a subset of OED that progress to carcinoma.

Oncological outcomes in rats given nephrocarcinogenic exposure to dietary ochratoxin a, followed by the tumour promoter sodium barbital for life: a pilot study

The potent experimental renal carcinogenesis of ochratoxin A (OTA) in male rats makes the dietary contaminant a potential factor in human oncology. We explored whether the tumour promoter sodium barbitate could shorten the otherwise long latency between exposure to toxin and tumourigenesis. Young rats, of a hybrid in which mononuclear leukaemia was rare, were given feed contaminated (5 ppm) with OTA for 36 weeks to initiate renal tumourigenesis. Some individuals were thereafter given sodium barbitate (500 ppm in drinking water) for life. Pathological outcomes were studied at or near the end of natural life. Renal tumours in males given barbitate became evident after latency of one year, but only slightly before those without barbitate. In contrast, female mammary tumourigenesis was advanced by at least 6 months synchronously in all rats given the OTA-barbitate regimen compared to tumourigenesis in controls. Diagnosis of malignant mammary angiosarcoma in a female given the OTA-barbitate regimen is a new finding in the rat. The long latency of OTA-induced renal tumourigenesis was not notably susceptible to accelerated promotion by barbitate, contrasting with an apparently marked effect of barbitate on development of mammary tumours.

A pilot study of nuclear instability in archived renal and upper urinary tract tumours with putative ochratoxin aetiology

DNA ploidy measurement has been applied uniquely to wax-embedded tissue of primary renal cell and metastatic tumours of a key experimental researcher on porcine ochratoxicosis, a control, and four transitional cell carcinomas from cases of Balkan endemic nephropathy. Primary renal tumour was diploid, and hyperdiploid metastasis was within the lower ploidy range for typical renal cell carcinoma. Three Balkan primary tumours showed extensive aneuploidy indicating marked nuclear instability, similar to model rat renal carcinoma caused by ochratoxin A. In contrast, much less nuclear instability in the putative occupational ochratoxicosis case fitted poorly with the ochratoxin A model.

Ploidy study in oral carcinomas: use of improved methodology to assess its clinical prognostic value

OBJECTIVE

This study reports a ploidy analysis in oral squamous cell carcinomas (SCC) using methodologic adjustments to improve the accuracy of the measurements and derive numeric indices of aggressiveness of prognostic value.

STUDY DESIGN

Sixty-seven SCC were assessed by DNA image cytometry in the areas of the histologic sections with most atypia. Five indices of aggressiveness were analyzed in relation to the clinical-pathologic data and evolution of the patients.

RESULTS

The mean value of the index of deviation from the diploid value (2cDi) and malignancy index (Mi), taken as a cut-off value, defined 2 populations with statistically significant differences in survival. In patients with tumors in clinical stages III and IV (TNM classification), the Mi also exhibited prognostic value.

CONCLUSIONS

The 2cDi and Mi can be used, under certain methodologic conditions, as an objective indicator of prognostic value of the degree of aggressiveness of oral SCC.

DNA ploidy analysis by image cytometry helps to identify oral epithelial dysplasias with a high risk of malignant progression

Abnormal DNA content (aneuploidy) has been associated with malignant and premalignant epithelial lesions. The presence of aneuploidy in tumours at an early stage and in dysplastic lesions suggests that analysis of DNA content may be a useful marker for determination of prognosis in these lesions. The aim of this study was to use DNA image cytometry to evaluate aneuploidy in oral dysplastic lesions and to determine whether aneuploidy is associated with malignant progression. Forty-two lesions of oral epithelial dysplasias (OED) that had progressed to oral squamous cell carcinoma (OSCC) and 44 lesions that did not progress were analysed for DNA ploidy using image cytometry of nuclear monolayers prepared from paraffin-embedded tissue. Forty-two OSCC that had arisen from the OED cases and five samples of normal oral mucosa samples (NOM) were also examined. Aneuploidy was found in 14/42 (33.3%) of the OED that progressed, but in only 5/44 (11.3%) of OED that did not progress (p=0.01). A total of 19 OED were aneuploid of which 74% showed malignant progression compared to only 42% of the diploid lesions. The sensitivity and specificity of DNA image cytometry to detect cases with high risk of malignant progression was 0.33 and 0.88, respectively. The PPV and NPV were 0.74 and 0.58. We conclude that aneuploid oral dysplastic lesions have a high risk of malignant progression and that DNA image cytometry might help to identify those lesions most at risk.

DNA ploidy distribution in renal tumours induced in male rats by dietary ochratoxin A

DNA ploidy distribution, measured in experimental renal tumours that occurred in twelve ageing male Fischer rats derived from carcinogenicity experiments on ochratoxin A (OTA) in response to chronic dietary exposure, was diploid in all renal adenomas and aneuploid in all carcinomas, correlating with their typical organised and disorganised histopathology, respectively. Aneuploidy was also detected in renal tissue in which karyomegaly, induced by OTA, was analogous to that caused by the fungus Penicillium polonicum. Thus, the experimental rat renal carcinoma could arise within an adenoma directly from certain persistent karyomegalic tubular epithelial cells long after their particular genetic damage has been caused during a protracted period of OTA insult.

ERBB receptors in developing, dysplastic and malignant oral epithelia

Some oral squamous cell carcinomas (OSCCs) overexpress epidermal growth factor receptor (EGFR) but little is known about the receptor system overall during oral carcinogenesis. We studied all four ERBB receptors (EGFR, ERBB2-4) in developing (n=2), normal (n=7), dysplastic (n=23) and malignant (n=26) oral epithelia by means of immunohistochemistry. The investigations were supplemented by conducting reverse transcription-polymerase chain reactions in relation to 13 OSCC samples. All four ERBB receptors were detected in developing oral epithelium and, to a lesser degree, in mature oral epithelium. An increase in EGFR immunoreactivity was seen in 61% and 54% of dysplasias and OSCCs, respectively. The corresponding percentages for ERBB2 were 48 and 12, for ERBB3 48 and 43. ERBB4 nuclear staining was increased in 30% of dysplasias and 26% of OSCCs. Changes in ERBB receptor mRNA levels were not statistically significant. The results show that ERBB receptor profiles are specific to each tumour. Increased nuclear translocation of ERBB4 in some OSCCs may alter transcription of target genes and be associated with cancer progression. This information may be useful for clinicians as EGFR inhibitors are becoming treatment options in modern oncology.

DNA ploidy analysis in salivary gland tumours by image cytometry

AIM

To determine whether DNA ploidy by image cytometry is a good diagnostic tool to distinguish benign and malignant salivary gland tumours.

METHODS

A total of 62 salivary gland tumours were studied. Cases were histologically diagnosed [haematoxylin and eosin (H&E)]. According to the World Health Organization (WHO) classification, there were 14 mucoepidermoid carcinomas (MEC), 11 adenoid cystic carcinomas (ACC), 10 pleomorphic adenomas (PA), 10 carcinoma ex PA (CEPA), 9 acinic cell carcinomas (ACCa), 3 polymorphous low-grade adenocarcinomas (PLGA), 2 papillary cystadenocarcinomas (PC), 1 myoepithelial carcinoma (MC), 1 undifferentiated carcinoma (UC) and 1 mucinous adenocarcinoma (MA). Paraffin sections (40 microm) were micro-dissected to isolate tumour areas; cell nuclei were extracted and Feulgen-stained cytospin monolayers were analysed using a DNA image cytometry system. For each case, DNA index (DI) was calculated relative to internal controls (lymphocytes; DI=1.0). Cases were categorized as diploid or aneuploid and the proportion of cells over 5c was also calculated.

RESULTS

Fifty-three of 62 salivary gland tumours were uniformly diploid. Only nine cases were aneuploid: five CEPA, one low-grade MEC, one PC, one UC and one MA.

CONCLUSIONS

The vast majority of salivary gland tumours were diploid. High-grade malignancies may be aneuploid, and ploidy may be useful to identify malignant change in atypical PA. Further, larger studies are needed to confirm our results and to further evaluate the usefulness of the technique in high-grade lesions.

DNA ploidy in proliferative verrucous leukoplakia

Proliferative verrucous leukoplakia (PVL) is a clinicopathologically distinctive form of oral leukoplakia presenting with multifocal flat, nodular and verrucous lesions that progress inexorably to squamous carcinoma. The aims of this investigation were to describe the clinical and histopathological features of six cases of PVL and to determine whether lesional epithelium demonstrates DNA ploidy anomalies prior to malignant transformation. The clinical and pathological features of six patients were reviewed and all biopsy specimens were subjected to image-based DNA ploidy analysis. The female:male ratio was 5:1 and the average age on first biopsy was 66 years. Only one patient reported both tobacco smoking and alcohol intake. The most frequently affected sites were alveolar ridge and/or gingiva (6/6), buccal mucosa (3/6), palate (3/6), tongue (2/6), buccal sulcus (2/6), and lip (1/6). Three patients developed multiple primary carcinomas, either invasive or verrucous. A ploidy anomaly at any oral site would have predicted malignant transformation in four cases and probably in a fifth for whom DNA ploidy failed to meet diagnostic criteria but was suspicious of aneuploidy. The site of transformation was predicted by ploidy and histopathology for three carcinomas and a further carcinoma showed severe dysplasia and a suspicious ploidy result in adjacent tissue. Both conventional histopathology and DNA ploidy proved effective in predicting the site of transformation in this limited series.

Oral squamous cell carcinoma: review of prognostic and predictive factors

Oral squamous cell carcinoma has a remarkable incidence worldwide and a fairly onerous prognosis, encouraging further research on factors that might modify disease outcome. In this review article, the authors approach the factors that may exert influence on the prognosis and eventually guide the selection of patients for more aggressive therapies. Published scientific data was collected, selected, and grouped into 3 main clusters: patient-, tumor-, and treatment-related factors. Well established aspects are discussed, but also those less common or with only supposed usefulness. Disease staging, extracapsular dissemination, resection margin free of disease, and tumor thickness are factors with high influence on the prognosis. There has been an increasing interest in the study of tumor molecular factors, and some have been strongly correlated with the outcome, showing promising pathways for the future development of more effective prognosis systems and anticancer therapies.