Can immunohistochemistry serve as an alternative to subjective histopathological diagnosis of oral epithelial dysplasia?

Evaluation of Heterogeneous Nuclear Ribonucleoprotein D Expression as a Diagnostic Marker for Oral Squamous Cell Carcinoma

The heterogeneous nuclear ribonucleoprotein D (hnRNPD) serves as a prognostic marker for oral squamous cell carcinoma (OSCC). We evaluated the diagnostic potential of hnRNPD to differentiate between OSCC and normal mucosa. Immunohistochemistry for hnRNPD and a routinely used diagnostic marker deltaNp63 (p40) was performed in 32 normal mucosae and 46 OSCC specimens. Subsequently, receiver-operating characteristic analysis was performed to evaluate the diagnostic potential of hnRNPD in comparison to that of p40. Immunostaining for p40 and hnRNPD was observed in 39 (84.78%) and 38 (82.60%) cases, respectively, in OSCC specimens. The poorly differentiated squamous cell carcinoma displayed 100% (eight cases) immunoreactivity for hnRNPD as compared to 87.5% (seven cases) for p40. Nuclear staining of p40 and hnRNPD was observed in all OSCC specimens. p40 staining was restricted to basal cells, whereas both basal and para-basal cells displayed hnRNPD staining in OSCC specimens. Areas under the curve for p40 and hnRNPD were 0.86 and 0.87, respectively. p40 and hnRNPD showed equal sensitivities (80.95%). However, hnRNPD displayed marginally higher (88.23%) specificity for tumor cells as compared to that of p40 (85.29%). Conclusion: In addition to being a well-established prognostic marker, hnRNPD can serve as a diagnostic marker for OSCC.

Oral Potentially Malignant Disorders (OPMD): What is the clinical utility of dysplasia grade?

INTRODUCTION

Oral epithelial dysplasia is considered a potential histologic precursor of subsequent squamous cell cancer. As standard clinical practice, pathologists grade dysplasia to assess risk for progression to malignancy. Except for the most advanced grade, severe dysplasia, dysplasia grading has failed to correlate well with the risk to develop invasive cancer. The questions of what process dysplasia grading best represents and what clinical utility dysplasia grading may have are explored.

AREAS COVERED

This narrative review is based on PubMed search with emphasis on papers since 2010. Epithelial dysplasia as a precursor lesion of cancer and dysplasia grading as a risk assessment tool for progression to cancer are discussed. The close clinical association of dysplasia with known carcinogens, alcohol, and tobacco products is presented.

EXPERT OPINION

Oral epithelial dysplasia is often, associated with prolonged exposure to tobacco and alcohol products. With reduction of carcinogen exposure, dysplasia is known to regress in some cases. It is proposed that histologic dysplasia grade together with macroscopic images of dysplastic clinical lesions be used as an educational tool to incentivize patients to reduce their known carcinogen exposure. This strategy has the potential to reduce lesion progression thereby reducing the disease burden of oral cancer.

Role of Electron Microscopy in Early Detection of Altered Epithelium During Experimental Oral Carcinogenesis

Early detection of altered epithelium can help in controlling the further progression by timely intervention. Alterations in cellular adhesion are one of the hallmarks of cancer progression, which can be detected at the intracellular level using high-resolution electron microscopy. This study aimed to evaluate the role of electron microscopy in the establishment of ultrastructural markers for early detection of altered epithelium using tissues from 4-Nitroquinoline-1-Oxide (4NQO) induced rat tongue carcinogenesis. Our previous study using light microscopy displayed no histopathological alterations in 4NQO treated tissues until 40 days of treatment, while dysplasia, papilloma and carcinoma were detected at 80/120, 160 and 200 days, respectively. However, electron microscopy detected alterations such as detachment of desmosomes from cell membranes and their clustering in the cytoplasm, increased tonofilaments, keratohyaline granules and thickened corneum in 40 days treated corresponding tissues. These alterations are apparent with hyperkeratosis/hyperplasia but remained undetected using light microscopy. Further, in dysplasia, papilloma and carcinoma, gradual and significant loss of desmosomes, leading to the significant widening of intercellular spaces, was observed using iTEM software. These parameters may serve as indicators for progression of oral cancer. Our results highlight the importance of electron microscopy in the early detection of subcellular changes in the altered epithelium.

Evaluation of Mast Cell Density in the Tumor Microenvironment in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

The objective of this study was to compare mast cell density (MCD) in oral epithelial dysplasias (OED) and oral squamous cell carcinoma (OSCC) and determine its correlation with clinical and histopathologic parameters and the degree of tumor differentiation. Thirty OSCC samples, 14 OED samples, and 4 non-neoplastic oral mucosa samples were analyzed by immunohistochemistry to determine MCD based on the expression of MC tryptase. In addition, MCs were categorized morphologically into degranulated and granulated cells. MCD was significantly higher in OSCC lesions with a greater degree of differentiation (P=0.04). No significant difference in MCD was detected between mild and moderate OED samples (P=0.09). Our findings indicate that MCs are present in the tumor microenvironment and may be associated with a better prognosis.

PI3K-AKT-mTOR pathway proteins are differently expressed in oral carcinogenesis

BACKGROUND

PI3K-AKT-mTOR signaling pathway is associated with several cellular functions and is frequently changed in several malignancies. The aim of this study was to characterize the immunohistochemical expression pattern of components in PI3K-AKT-mTOR signaling pathway in oral epithelial dysplasia (OED), comparing to oral squamous cell carcinoma (OSCC) and non-dysplastic oral tissues (NDOT).

METHODS

A total of 186 cases of NDOT, OED and OSCC were retrieved. Nuclear staining and cytoplasmic staining of the keratinocytes were considered positive, and the percentage of positive cells was calculated.

RESULTS

Increased immunoreactivity from NDOT to OED and OSCC was seen for all proteins. In NDOT cases, positivity was found only for pS6 (52.9%) and p4EBP1 (13.5%). In OED, immunoreactivity was observed for pAKT (62.2%), pmTOR (28.6%), pS6 (70.8%), and p4EBP1 (42.9%). In OSCC cases, immunoreactivity was found for pAKT (83.3%), pmTOR (50%), pS6 (77.4%), and p4EBP1 (50%). The pAKT and pmTOR expression was higher in OED (<0.001, Fisher's exact test) and OSCC (<0.001, Fisher's exact test).

CONCLUSION

Our study demonstrated higher pAKT and pmTOR expression during carcinogenesis of oral mucosa, differing considerably among OED and OSCC specimens when compared to NDOT. These proteins can be considered potential diagnostic markers for early detection of cancer.

Fourier-transform-infrared-spectroscopy based spectral-biomarker selection towards optimum diagnostic differentiation of oral leukoplakia and cancer

In search of specific label-free biomarkers for differentiation of two oral lesions, namely oral leukoplakia (OLK) and oral squamous-cell carcinoma (OSCC), Fourier-transform infrared (FTIR) spectroscopy was performed on paraffin-embedded tissue sections from 47 human subjects (eight normal (NOM), 16 OLK, and 23 OSCC). Difference between mean spectra (DBMS), Mann-Whitney's U test, and forward feature selection (FFS) techniques were used for optimising spectral-marker selection. Classification of diseases was performed with linear and quadratic support vector machine (SVM) at 10-fold cross-validation, using different combinations of spectral features. It was observed that six features obtained through FFS enabled differentiation of NOM and OSCC tissue (1782, 1713, 1665, 1545, 1409, and 1161 cm(-1)) and were most significant, able to classify OLK and OSCC with 81.3 % sensitivity, 95.7 % specificity, and 89.7 % overall accuracy. The 43 spectral markers extracted through Mann-Whitney's U Test were the least significant when quadratic SVM was used. Considering the high sensitivity and specificity of the FFS technique, extracting only six spectral biomarkers was thus most useful for diagnosis of OLK and OSCC, and to overcome inter and intra-observer variability experienced in diagnostic best-practice histopathological procedure. By considering the biochemical assignment of these six spectral signatures, this work also revealed altered glycogen and keratin content in histological sections which could able to discriminate OLK and OSCC. The method was validated through spectral selection by the DBMS technique. Thus this method has potential for diagnostic cost minimisation for oral lesions by label-free biomarker identification.

Keratosis of unknown significance and leukoplakia: a preliminary study

OBJECTIVE

The objectives were to (1) determine the frequency of specific diagnoses in a series of white lesions, and (2) describe the nature of keratotic lesions that are neither reactive nor dysplastic.

STUDY DESIGN

White lesions were analyzed and diagnosed as reactive keratoses, dysplastic/malignant, or keratoses of unknown significance (KUS).

RESULTS

Of the 1251 specimens that were evaluated, 703 met criteria for inclusion, and approximately 75% were reactive, 10% dysplastic/malignant, and 14% KUS. Excluding reactive keratoses, 43% were dysplastic/malignant and 57% were KUS.

CONCLUSIONS

Reactive keratoses were the most common white lesions followed by lichen planus. Dysplastic/malignant lesions constituted almost 50% of all true leukoplakias. KUS constituted the remaining cases and do not show typical reactive histopathology as well as clear dysplasia. They may represent evolving or devolving reactive keratoses but may also represent the very earliest dysplasia phenotype. Clinical findings may be helpful in differentiating the two.