Iona Leong

EWSR1‐ATF1 fusion is a novel and consistent finding in hyalinizing clear‐cell carcinoma of salivary gland

Hyalinizing clear‐cell carcinoma (HCCC) is a rare, low‐grade salivary gland tumor with distinctive clear‐cell morphology and pattern of hyalinization as well as focal mucinous differentiation. However, histological overlap exists with other salivary gland tumors, such as epithelial–myoepithelial carcinoma (EMCa), salivary myoepithelial carcinoma, and mucoepidermoid carcinoma (MEC). The potential relationship between HCCC and its morphological mimics has not been yet investigated at the genetic level. In this study, we conducted a molecular analysis for the presence of rearrangements in MAML2, commonly seen in MECs, and EWSR1, involved in “soft tissue myoepithelial tumors” (SMET) by fusion with POU5F1, PBX1, or ZNF444. Fluorescence in situ hybridization (FISH) was performed on 23 HCCC cases for abnormalities in MAML2, EWSR1, FUS, POU5F1, PBX1, and ZNF444. FISH for MAML2 was negative in all cases (0 of 14), including those with mucinous differentiation (0 of 7). An EWSR1 rearrangement was identified in 18 of 22 HCCCs (82%), while no break‐apart signals were seen in FUS, POU5F1, PBX1, or ZNF444. 3′RACE on an EWSR1 rearranged HCCC identified an EWSR1‐ATF1 fusion, which was confirmed by RT‐PCR. ATF1 involvement was further confirmed by FISH analysis in 13 of 14 EWSR1‐rearranged HCCC cases (93%). In contrast, all control cases tested, including among others 5 EMCa and 3 MEC with clear cells, were negative for EWSR1 and ATF1 rearrangements. The presence of EWSR1‐ATF1 fusion in most HCCCs reliably separates these tumors from its histological mimics. The distinction from MEC is particularly important, as conventional MEC grading schemes overgrade these indolent HCCCs, potentially impacting on treatment.

Clear cell carcinoma: Review of its histomorphogenesis and classification as a squamous cell lesion

In current classification schemes, clear cell carcinoma-including both the hyalinized and nonhyalinized variety--is now an accepted subtype of malignant salivary gland tumors. Despite this, the underlying cellular differentiation process leading to the typical histomorphology of this neoplasm remains unclear. This review summarizes and illustrates the histologic, ultrastructural, and immunohistochemical evidence for the underlying squamous cell nature of clear cell carcinoma. Squamous cell differentiation is not an uncommon feature of nonneoplastic and neoplastic lesions of the salivary glands. Clear cell carcinoma needs to be added to this list as a unique but specific variety of clear cell squamous carcinoma.

S100A7 overexpression is a predictive marker for high risk of malignant transformation in oral dysplasia

Early detection of oral lesions (OLs) at high risk of cancer development is of utmost importance for intervention. There is an urgent unmet clinical need for biomarkers that allow identification of high‐risk OLs. Recently, we identified and verified a panel of five candidate protein biomarkers namely S100A7, prothymosin alpha, 14‐3‐3ζ, 14‐3‐3σ and heterogeneous nuclear ribonucleoprotein K using proteomics to distinguish OLs with dysplasia and oral cancers from normal oral tissues. The objective of our study was to evaluate the potential of these candidate protein biomarkers for identification of oral dysplastic lesions at high risk of cancer development. Using immunohistochemistry, we analyzed expressions of these five candidate protein biomarkers in 110 patients with biopsy‐proven oral dysplasia and known clinical outcome and determined their correlations with p16 expression and HPV 16/18 status. Kaplan–Meier survival analysis showed reduced oral cancer‐free survival (OCFS) of 68.6 months (p = 0.007) in patients showing cytoplasmic S100A7 overexpression when compared to patients with weak or no S100A7 immunostaining in cytoplasm (mean OCFS = 122.8 months). Multivariate Cox regression analysis revealed cytoplasmic S100A7 overexpression as the most significant candidate marker associated with cancer development in dysplastic lesions (p = 0.041, hazard ratio = 2.36). In conclusion, our study suggested the potential of S100A7 overexpression in identifying OLs with dysplasia at high risk of cancer development.

Prediction of recurrence-free survival using a protein expression-based risk classifier for head and neck cancer

Loco-regional recurrence in 50% of oral squamous cell carcinoma (OSCC) patients poses major challenge for oncologists. Lack of biomarkers that can predict disease aggressiveness and recurrence risk makes the scenario more dismal. On the basis of our earlier global proteomic analyses we identified five differentially expressed proteins in OSCC. This study aimed to develop protein biomarkers-based prognostic risk prediction model for OSCC. Sub-cellular expression of five proteins, S100A7, heterogeneous nuclear ribonucleoproteinK (hnRNPK), prothymosin α (PTMA), 14-3-3ζ and 14-3-3σ was analyzed by immunohistochemistry in test set (282 Indian OSCCs and 209 normal tissues), correlated with clinic–pathological parameters and clinical outcome over 12 years to develop a risk model for prediction of recurrence-free survival. This risk classifier was externally validated in 135 Canadian OSCC and 96 normal tissues. Biomarker signature score based on PTMA, S100A7 and hnRNPK was associated with recurrence free survival of OSCC patients (hazard ratio=1.11; 95% confidence interval 1.08, 1.13, P<0.001, optimism-corrected c-statistic=0.69) independent of clinical parameters. Biomarker signature score stratified OSCC patients into high- and low-risk groups with significant difference for disease recurrence. The high-risk group had median survival 14 months, and 3-year survival rate of 30%, whereas low-risk group survival probability did not reach 50%, and had 3-year survival rate of 71%. As a powerful predictor of 3-year recurrence-free survival in OSCC patients, the newly developed biomarkers panel risk classifier will facilitate patient counseling for personalized treatment.

Association of human papilloma virus with atypical and malignant oral papillary lesions.

OBJECTIVE This study aimed to examine atypical and malignant papillary oral lesions for low- and high-risk human papillomavirus (HPV) infection and to correlate HPV infection with clinical and pathologic features. STUDY DESIGN Sections of 28 atypical papillary lesions (APLs) and 14 malignant papillary lesions (MPLs) were examined for HPV by in situ hybridization and for p16 and MIB-1 by immunohistochemistry; 24 conventional papillomas were studied for comparison. RESULTS Low-risk HPV was found in 10 of 66 cases, including 9 APLs and 1 papilloma. All low-risk HPV-positive cases showed suprabasilar MIB-1 staining, and the agreement was statistically significant (P < .0001). Diffuse p16 staining combined with high-risk HPV was not seen in any of the cases. A subset of HPV(-) APLs progressed to carcinoma. CONCLUSIONS Oral papillary lesions are a heterogeneous group. Low-risk HPV infection is associated with a subset of APLs with a benign clinical course. Potentially malignant APLs and MPLs are not associated with low- or high-risk HPV.

Radiation-induced craniofacial bone growth inhibition: acute and long-term effects on bone histopathology with and without cytoprotection.

Background: The authors previously established an animal model of radiation-induced craniofacial bone growth inhibition and demonstrated the effectiveness of cytoprotection in preserving growth using amifostine, but the mechanism is unclear. The objective of this study was to investigate the acute and long-term histopathologic effects of single-dose orthovoltage irradiation on craniofacial bone with and without cytoprotection. Methods: Sixty infant New Zealand White rabbits (7-week-old) were randomized into three groups (n = 20 per group): group 1, 0-Gy, sham irradiation; group 2, 35-Gy single-dose orthovoltage irradiation; and group 3, cytoprotection with amifostine before irradiation. Orbitozygomatic complex bone was harvested from animals 12 hours after irradiation and at skeletal maturity (21 weeks of age). Histologic parameters measured included native bone cell (osteoblast, osteoclast, and osteocyte) populations, periosteal proliferation indices (MIB-1 stains), bone turnover rates [triple fluorochromes: tetracycline administered at 7 weeks of age (before irradiation), alizarin complexone at 12 weeks, and calcein at 16 weeks of age], and endosteal space fibrosis levels. Results: Orthovoltage irradiation significantly (p < 0.05) reduced osteoblast and osteoclast counts 12 hours after irradiation (age, 7 weeks) with or without pretreatment with amifostine but had no effect on osteocyte populations. Long-term analysis at age 21 weeks demonstrated significantly (p < 0.05) increased osteoblast counts, reduced endosteal space fibrosis, reduced periosteal proliferation indices, and improved bone turnover (fluorochrome stains) in amifostine-treated animals. Conclusion: This study suggests that amifostine cytoprotection is mediated through a combination of reduced cellular injury with enhanced promotion of cellular bone rebuilding potential.

Oral Manifestations of Immunologically Mediated Diseases

Oral mucosal swelling, ulceration or red-white lesions may be caused by an aberrant immune response. Clinical history is important to identify any trigger for the aberrant immune response; removal of the trigger will lead to resolution of the mucosal lesion. Clinical investigations may be needed to determine if the oral lesions are associated with extraoral lesions, which may indicate an underlying systemic disease. Incisional biopsy is useful for diagnosis of some conditions, whereas other conditions are diagnosed by clinical history and appearance. Symptomatic treatment may be provided if no known trigger or causative factor can be found.