Sharon Akrish

Oral cancer, cigarette smoke and mitochondrial 18 kDa translocator protein (TSPO) — In vitro, in vivo, salivary analysis

Oral cancer features high rates of mortality and morbidity, and is in dire need for new approaches. In the present study we analyzed 18 kDa translocator protein (TSPO) expression in oral (tongue) cancer tumors by immunohistochemistry. We also assayed TSPO binding in human tongue cancer cell lines and in the cellular fraction of saliva from tongue cancer patients, heavy cigarette smokers, and non-smoking healthy people as controls. Concurrently, TSPO protein levels, cell viability, mitochondrial membrane potential (Deltapsi(m)), and general protein levels were analyzed. TSPO expression could be significantly enhanced in oral cancer tumors, compared to unaffected adjacent tissue. We also found that five-year survival probability dropped from 65% in patients with TSPO negative tumors to 7% in patients with highly expressed TSPO (p<0.001). TSPO binding capacity was also pronounced in the human oral cancer cell lines SCC-25 and SCC-15 (3133+/-643 fmol/mg protein and 6956+/-549 fmol/mg protein, respectively). Binding decreased by 56% and 72%, in the SCC-25 and SCC-15 cell lines, respectively (p<0.05) following CS exposure in cell culture. In the cellular fraction of saliva of heavy smokers TSPO binding was lower than in non-smokers (by 53%, p<0.05). Also the cellular fraction of saliva exposed to CS in vitro showed decreased TSPO binding compared to unexposed saliva (by 30%, p<0.001). Interestingly, oral cancer patients also displayed significantly lower TSPO binding in the cellular fraction of saliva compared to healthy controls (by 40%, p<0.01). Our results suggest that low TSPO binding found in the cellular fraction of saliva may depend on genetic background as well as result from exposure to CS. We suggest that this may be related to a predisposition for occurrence of oral cancer.

Heparanase up-regulation in tongue cancer: tissue and saliva analysis.

Heparanase up‐regulation has been correlated with reduced postoperative survival in various cancers.

Oral squamous cell carcinoma associated with proliferative verrucous leukoplakia compared with conventional squamous cell carcinoma—a clinical, histologic and immunohistochemical study

OBJECTIVE Proliferative verrucous leukoplakia (PVL), a potentially malignant disorder, often undergoes malignant transformation to oral squamous cell carcinoma. The aim of our study was to document and compare the histologic, immunohistochemical, and clinical features and the survival rates of carcinoma arising in patients with PVL (p-scca) with conventional squamous cell carcinoma (c-scca) in order to determine if p-scca should be categorized as a separate clinical entity. MATERIALS AND METHODS A retrospective review of 11 patients with PVL, 38 with p-scca tumors and 49 with c-scca tumors: buccal mucosa (n = 28) and gingiva or palate (n = 21). Immunohistochemistry was performed by using antibodies directed against p16, p53, and ki67. RESULTS P-scca had lower clinical stage (P = .0001), smaller tumor size (P = .0033), no lymph node metastasis (P = .0002) or distant metastasis (P = .05), and better short term (P = .03), but not long term (P = .12) survival. Microscopically, p-scca tumor thickness was significantly less (P = .0001). P-53 overexpression was more common in p-scca (P = .0043) but not ki67 or p16 overexpression. CONCLUSIONS P-scca, compared with c-scca, presented with significantly better prognostic factors and short-term survival rates and longer duration of disease. Our results suggest that p-scca may represent a distinct entity, which may have practical implications when deciding on treatment. Further studies on a larger cohort of patients are recommended.

Improving the rate of negative margins after surgery for oral cavity squamous cell carcinoma: A prospective randomized controlled study.

A positive margin is among the most significant factors that affects the outcome in head and neck squamous cell carcinoma (SCC). The purpose of this study was to compare the negative margin rates between 2 methods of intraoperative margin assessment in patients with oral cavity SCC.

Ki67 and Salivary Cancer

We examined Ki67 expression in salivary malignancies of 75 patients with a follow-up period of up to 20 years. Correlations between enhanced Ki67 and enhanced p53 and TUNEL and heparanase staining levels were significant. Median survival for reduced-stained-tumor patients (≤ 5%) was 163 months, dropping significantly to 39 months (p = 0.0005) for enhanced stained tumors (> 5%); 5 year survival probability was 93% and 33%, respectively, 45% and 16%, respectively, (p = 0.0005) at 20 years. Significant correlation between poor survival and concurrently altered expression rates of Ki67 and p53, p27 Skp2, TUNEL and heparanase in the salivary malignancies indicates a biological role in salivary cancer pathogenesis.

Skp2 and salivary cancer.

Salivary malignancies are rare, heterogeneous, unpredictable in clinical behavior and seldom studied. Skp2 expression was examined in salivary malignancies (n=75) for a prolonged period (20 years). In 40/75 (53%) cases Skp2 expression rate (staining level) was ≤4% while in the remainder (47%) it was >4%. Correlation between enhanced Skp2 and enhanced p53 staining levels was significant (p=0.042), as were correlation rates between enhanced Skp2 and reduced p27 staining levels (p=0.01) and enhanced Skp2 and enhanced TUNEL staining levels (p=0.008). Survival probability rates dropped when Skp2 expression increased. Median patient survival for reduced-stained-tumor patients (≤4%) was 143 months and significantly lower, 49 months (p=0.016), for enhanced-stained-tumor patients (>4%). Survival probability at 5 years was 82% for the former group (≤4%) and 47% for the latter (>4%). At 20 years, survival dropped to 35% and 18% respectively (p=0.016). More extensive and aggressive therapy did not reduce mortality in patients with enhanced Skp2-expressing tumors. Significant correlations between poor survival and significantly altered expression rates of Skp2, p27, p53, TUNEL and heparanase in salivary malignancies, suggest a biological role in salivary cancer pathogenesis for these 5 markers. The findings may be used for prognostic and follow-up purposes.

BRAF and GNAQ mutations in melanocytic tumors of the oral cavity

OBJECTIVE The genetic factors participating in oral melanoma evolution have not been studied extensively. We aimed to analyze the prevalence of BRAF and GNAQ mutations in a series of oral melanocytic tumors, nevi, and melanomas. STUDY DESIGN The study group consisted of 4 melanomas and 10 nevi (6 intramucosal, 4 blue nevi). DNA was extracted from paraffin-embedded tissue sections, and mutations in GNAQ and BRAF were analyzed with the use of mass spectrometery. RESULTS V600E point mutation was identified in the BRAF gene in 3 intramucosal nevi and in 2 melanomas. Only 1 blue nevus harbored the GNAQ209 mutation. None of the BRAF-positive samples harbored GNAQ mutations. CONCLUSIONS The finding of BRAF mutations in oral benign and malignant melanocytic lesions points to a potential initiating role of BRAF in malignant transformation, which may have important therapeutic implications as those with BRAF mutations may benefit from specific treatment using RAF inhibitors.

The salivary tip of the p53 mutagenesis iceberg: Novel insights

Salivary malignancies are rare, heterogeneous, unpredictable in their clinical behavior and seldom studied. This study focused on examining the expression of mutated p53, the most prevalent mutated gene related to human cancer, in a rather large cohort of salivary malignancies (n = 70) and for a prolonged period (20 years). P53 was found to be a most powerful predictor for poor survival and more so when the tumor concurrently expressed TUNEL and heparanase markers, dramatically dropping the survival probability of the patients to 0! Survival probability at 6 years for patients with tumors stained negatively vs. positively for p53, TUNEL and heparanase was 100% vs. 49% while at 18 years this probability dropped to 67% vs. 0%, respectively (p = 0.023). Significant correlation rates were found between age and poor survival, age and p53, and p53 and other co-existing malignancies. These findings support mutated p53 as a prognostic predictor and a pivotal player in salivary carcinogenesis. Significantly more extensive therapy applied to salivary p53-positive patients did not improve mortality rate, questioning the justification for such extensive therapy and emphasizing the need to understand p53, TUNEL and heparanase biological pathways and develop additional therapeutic tools for fighting salivary cancer.

Trends in human papillomavirus–related oropharyngeal cancer in Israel

The role of human papillomavirus (HPV) infection in oropharyngeal cancer (SCC) is well established. The annual incidence of oropharyngeal SCC in Israel is considerably lower than that in the United States. The purpose of this study was to assess the rate of HPV‐related oropharyngeal SCC in Israel.

Cancer associated fibroblasts are an infrequent finding in the microenvironment of proliferative verrucous leukoplakia associated squamous cell carcinoma

BACKGROUND Cancer-associated fibroblasts (CAFs) are generally associated with negative prognostic factors. This study compares the clinicopathologic impact of CAFs in oral squamous cell carcinoma in patients with a history of proliferative verrucous leukoplakia (p-scca) and patients with conventional squamous cell carcinoma of the buccal mucosa, gingiva, and palate (c-scca). METHODS A retrospective clinicopathologic and immunohistochemical analysis of 97 tumor specimens from 78 patients (13 patients with proliferative verrucous leukoplakia-associated squamous cell carcinoma (n = 32) and conventional squamous cell carcinoma from the buccal mucosa, gingiva, and palate (n = 65) was conducted. Immunostaining with anti-alpha-smooth muscle actin (α-SMA) antibody was used to evaluate the presence of CAFs. RESULTS α-SMA expression was an infrequent finding in p-scca and seen in only 6% of p-scca compared to 40% of c-scca (P < 0.0004). In the c-scca subgroup, α-SMA significantly correlated with tumor size (T) (P = 0.009), tumor thickness (P < 0.0009), perineural invasion (P = 0.009), and microscopic grade (P = 0.018). CONCLUSIONS The presence of CAFs was an infrequent finding in our p-scca cohort which may contribute to its seemingly slower growing and less invasive growth pattern. In the cohort of c-scca patients, higher levels of CAFs correlated with microscopic invasiveness, tumor size, and perineural invasion. Practically, these are important observations as targeting strategies are being developed to combat carcinoma types where CAFs significance has been validated.