Oral squamous cell carcinoma: overview of current understanding of aetiopathogenesis and clinical implications

Effect of curcumin and irradiation in PE/CA-PJ15 oral squamous cell carcinoma

OBJECTIVE

An in vitro study was made to evaluate the effect of curcumin and irradiation upon oral squamous cell carcinoma.

MATERIALS AND METHOD

Curcumin was administered at doses of 3, 3.75, 4.50 and 5.25 μM in PE/CA-PJ15 oral squamous cell carcinoma cultures irradiated with different doses (1, 2.5 and 5 Gy), followed by evaluation of the effects upon cell viability after 24, 48 and 72 h, based on the MTT colorimetric test.

RESULTS

The application of curcumin to the PECA/PJ15 tumor cells during 24, 48 and 72 h of incubation without irradiation exerted an inhibitor effect upon cell viability. The curcumin concentration at which the inhibition of cell viability proved maximum was 5.25 μM, with statistically significant differences for 24 h (p = 0.002), 48 h (p < 0.001) and 72 h of incubation (p < 0.001). In contrast, the combination of curcumin and irradiation exerted a synergic effect-the greatest effects in relation to cell viability being recorded with a curcumin concentration of 3.75 μM and 5 Gy of irradiation, in the studied cell line.

CONCLUSIONS

Curcumin increases cytotoxic activity in the PE/CA PJ15 cell line, while the combination of curcumin and irradiation exerts a synergic effect.

Enhanced programmed death 1 (PD-1) and PD-1 ligand (PD-L1) expression in patients with actinic cheilitis and oral squamous cell carcinoma

PD-1 and PD-L1 can be involved in tumor escape, and little is known about the role of these molecules in oral tumors or pre-malignant lesions. In the present study, we investigated the expression of PD-1 and PD-L1 in the blood and lesion samples of patients with actinic cheilitis (AC) and oral squamous cell carcinoma (OSCC). Our results showed that lymphocytes from peripheral blood and tissue samples exhibited high expression of PD-1 in both groups analyzed. Patients with AC presented higher percentage as well as the absolute numbers of CD4+PD-1+ and CD8+PD-1+ lymphocytes in peripheral blood mononuclear cells (PBMC) than healthy individuals, while patients with OSCC presented an increased frequency of CD8+PD1+ in PBMC when compared with controls. On the other hand, increased frequency of CD4+ and CD8+ T cells expressing PD-1(+) accumulate in samples from OSCC, and the expression of PD-L1 was intense in OSCC and moderate in AC lesion sites. Lower levels of IFN-γ and higher levels of TGF-β were detected in OSCC samples. Our data demonstrate that PD-1 and PD-L1 molecules are present in blood and samples of AC and OSCC patients. Further studies are required to understand the significance of PD-1 and PD-L1 in oral tumors microenvironment.

Analysis of RNA from brush cytology detects changes in B2M, CYP1B1 and KRT17 levels with OSCC in tobacco users

RNA expression analysis of oral keratinocytes can be used to detect early oral cancer, but a limitation is the inability to obtain high quality RNA from oral tissue without using biopsies. While oral cytology cell samples can be obtained from patients in a minimally invasive manner, they have not been validated for quantitative analysis of RNA expression. Earlier we showed RNA from brush cytology of hamster Oral Squamous Cell Carcinoma (OSCC) demonstrated differential expression of B2M and CYP1B1 using real time RT-PCR in a dibenz[a,I]pyrene, tobacco carcinogen, induced model of this disease. Here we show reproducibility of this approach to measuring gene expression in humans. Cytology brush samples from 12 tobacco and betel related OSCC and 17 nonmalignant oral lesions revealed B2M mRNA was enriched in tumor samples while CYP1B1 mRNA was reduced, similar to what was seen in the model system. Additionally, we showed that KRT17 mRNA, a gene linked to OSCC in another brush cytology study, was also enriched in OSCC versus nonmalignant lesions, again supporting the promise of using RNA from brush oral cytology to reproducibly monitor oral gene expression.

Lichen planus of the esophagus: what dermatologists need to know

BACKGROUND

Esophageal lichen planus (ELP) is a rare manifestation of mucocutaneous lichen planus (LP).

OBJECTIVES

We aimed to report our experience and review all cases of ELP reported in the English-language literature.

METHODS

We report our experience with 4 cases and reviewed PubMed for reports of ELP. Cases were evaluated for age of onset, sex, location of LP, relationship of the onset of ELP to extra-ELP, endoscopic findings, whether biopsy was performed, histopathology of esophageal biopsy specimens, medical history (including gastrointestinal history), development of esophageal squamous cell carcinoma, therapies tried, and response to treatment.

RESULTS

A total of 72 cases of ELP were studied. In all, 87% of patients were female, with a median age of 61.9 years at time of diagnosis. Dysphagia was present in 81% and odynophagia was present in 24%. Oral LP was present in 89%, anogenital/vulvar LP in 42%, and cutaneous LP in 38%. Fourteen patients developed ELP as the sole or first manifestation of LP. Proximal esophageal lesions were present in 64%, distal in 11%, and both proximal and distal in 26%. Histology was "consistent with" LP in 71%. Four patients developed squamous cell carcinoma in association with ELP.

LIMITATIONS

This is a review of our cases and others reported in the literature.

CONCLUSIONS

ELP is underrecognized and underreported. There is often a significant delay between the onset of symptoms and the diagnosis. Malignant transformation of ELP to squamous cell carcinoma has been reported.

Increase of ZASC1 gene copy number in recurrent oral carcinoma

BACKGROUNDS

The chromosome 3q26 locus is a hotspot region carrying oncogenes that frequently altered in neoplasms. ZASC1 is a zinc finger protein transcription factor localized on 3q26. Our previous study showed the frequent amplification of 3q26, including the ZASC1 gene, in oral squamous cell carcinoma (OSCC). This study investigated the copy number changes of ZASC1 gene from primary to recurrent OSCC and the functions of ZASC1 in OSCC cells.

MATERIALS AND METHODS

A total of 27 OSCC patients with primary and recurrent tumors were examined for ZASC1 and TERC copy number changes using Quantitative PCR analysis. Exogenous expression and knockdown of ZASC1 were carried out to specify the oncogenic potential of ZASC1 in OSCC cells.

RESULTS

A ZASC1 copy number that has increased from primary to recurrent tumor counterparts in tissue pairs suggested the importance of ZASC1 in tumor progression. The increase of ZASC1 gene copy number in recurrent tumors was associated with the consumption of betel quid in patients. OSCC cells expressing ZASC1-FLAG fusion protein showed increased proliferation. After the knockdown of endogenous ZASC1 expression using small interference RNA, the growth and colony formation of SAS OSCC cells decreased.

CONCLUSIONS

The findings support the hypothesis that ZASC1 localized on 3q26 contributes to the recurrence of OSCC.

Contemporary concepts in the diagnosis of oral cancer and precancer

This article addresses several issues in the approach to diagnosis of oral cancer. The term oral cancer is clarified. Key aspects of the biologic basis of development of oral cancer and the known risk factors associated with the disease are summarized. The clinical presentation of oral cancers and precancerous lesions and their histopathologic correlates is discussed. The importance of conventional tissue biopsy as the prevailing gold standard for diagnosis is emphasized. Other current technologies available for detecting and diagnosing oral cancer and premalignant lesions are acknowledged, and their respective strengths and weaknesses are discussed.

Right hand digit ratio (2D:4D) is associated with oral cancer

Finger length ratio has been proposed as a putative marker for prenatal hormone exposure, as well as the action of HOX, AR, and a variant of the LIN28b genes. These genes have been recently connected to carcinogenesis and digit ratio could help to identify patients with this predisposition.

OBJECTIVES

The purpose of this study was to investigate the possible correlations between digit ratio, oral squamous cell carcinoma (OSCC)-the most common oral cancer-and oral premalignant lesions (OPLs) in tobacco-consuming males, the main risk group for this disease.

METHODS

Digital images of the right hands of patients diagnosed with OSCC (n = 25), OPLs (n = 25), and age-matched controls (n = 25) were obtained. Fingers were measured using Adobe Photoshop and the mean ratios between the 2nd and 4th digits were compared. Data were analyzed by ANOVA (α = 0.05).

RESULTS

Risk factors (alcohol and tobacco consumption, familial history) were similar between the three study groups. Males in the OSCC group presented significantly higher digit ratio (P = 0.03) in comparison with males with OPLs and individuals without oral lesions.

CONCLUSIONS

According to the results, males with the higher digit ratio seem to be more prone to undergo malignization of lesions in the oral cavity. Similar deleterious habits for the three groups allows us to infer that digit ratio could add to the research of etiological factors and be a putative marker for the screening of patients' susceptibility to develop oral squamous cell carcinoma.

Significance of galectins-1, -3, -4 and -7 in the progression of squamous cell carcinoma of the tongue

The aim of this study was to analyze the immunohistochemical expression of galectins-1, -3, -4, and -7 in 65 cases of squamous cell carcinoma of the tongue and to correlate this expression with clinical (disease outcome, metastasis, and clinical stage) and morphological parameters (histological grade of malignancy). Clinical data were obtained from the patient records. The histological grading system of malignancy proposed by Bryne (1998) [9] was used for the analysis of morphological parameters. The results were analyzed statistically by χ(2) test (p < 0.05). Galectin-1 expression was observed in 87.7% of cases and was significantly correlated with metastasis (p = 0.033) and clinical stage (p = 0.016). Immunoexpression of galectin-3 was observed in 87.7% of cases and was correlated with the presence of metastasis (p = 0.033) and histological grade of malignancy (p = 0.031). Galectin-4 showed no significant correlation with any of the parameters studied. Expression of galectin-7 was observed in 73.8% of cases and was significantly correlated with the histological grade of malignancy (p = 0.005). In conclusion, the intense immunoexpression of galectins-1, -3, and -7 suggests the participation of these proteins in oral carcinogenesis and their use as markers of biological behavior and tumor progression in squamous cell carcinoma of the tongue.

Combined magnetic resonance and optical imaging of head and neck tumor xenografts using Gadolinium-labelled phosphorescent polymeric nanomicelles

BACKGROUND

The overall objective of this study was to develop a nanoparticle formulation for dual modality imaging of head and neck cancer. Here, we report the synthesis and characterization of polymeric phospholipid-based nanomicelles encapsulating near-infrared (NIR) phosphorescent molecules of Pt(II)-tetraphenyltetranaphthoporphyrin [Pt(TPNP)] and surface functionalized with gadolinium [Pt(TPNP)-Gd] for combined magnetic resonance imaging (MRI) and NIR optical imaging applications.

METHODS

Dynamic light scattering, electron microscopy, optical spectroscopy and MR relaxometric measurements were performed to characterize the optical and magnetic properties of nanoparticles in vitro. Subsequently, in vivo imaging experiments were carried out using nude mice bearing primary patient tumor-derived human head and neck squamous cell carcinoma xenografts.

RESULTS

The nanomicelles were ~100 nm in size and stable in aqueous suspension. T1-weighted MRI and relaxation rate (R1 = 1/T1) measurements carried out at 4.7 T revealed enhancement in the tumor immediately post injection with nanomicelles, particularly in the tumor periphery which persisted up to 24 hours post administration. Maximum intensity projections (MIPs) generated from 3D T1-weighted images also demonstrated visible enhancement in contrast within the tumor, liver and blood vessels. NIR optical imaging performed (in vivo and ex vivo) following completion of MRI at the 24 h time point confirmed tumor localization of the nanoparticles. The large spectral separation between the Pt(TPNP) absorption (~700 nm) and phosphorescence emission (~900 nm) provided a dramatic decrease in the level of background, resulting in high contrast optical (NIR phosphorescence) imaging.

CONCLUSIONS

In conclusion, Pt(TPNP)-Gd nanomicelles exhibit a high degree of tumor-avidity and favorable imaging properties that allow for combined MR and optical imaging of head and neck tumors. Further investigation into the potential of Pt(TPNP)-Gd nanomicelles for combined imaging and therapy of cancer is currently underway.

Immunoexpression of bone morphogenetic protein-2 (BMP-2), BMP receptor type IA, and BMP receptor type II in metastatic and non-metastatic lower lip squamous cell carcinoma

BACKGROUND

The aim of this study was to evaluate the expression of bone morphogenetic protein-2 (BMP-2), BMPR-IA, and BMPR-II in metastatic and non-metastatic lower lip squamous cell carcinoma (LLSCC).

METHODS

Twenty LLSCC with regional nodal metastasis and 20 LLSCC without metastasis were selected for analysis of the immunoexpression of BMP-2, BMPR-IA, and BMPR-II. The percentage of positive cells was evaluated according to the following parameters: score 1 (staining in 0-50% of cells), score 2 (staining in 51-75% of cells), and score 3 (staining in >75% of cells). Immunostaining intensity was evaluated according to the following scores: score 1 (absent or weak expression) and score 2 (strong expression).

RESULTS

Regarding the percentage of positive cells, most tumors with and without metastasis showed score 3 for both BMP-2 (P = 0.655) and BMPR-IA (P = 0.655). For BMPR-II, metastatic tumors exhibited higher percentage of positive cells in comparison with non-metastatic tumors (P = 0.049). With respect to immunostaining intensity, most LLSCCs with and without metastasis showed score 2 for BMP-2 (P = 1.000) and score 1 for BMPR-II (P = 1.000). For BMPR-IA, most metastatic tumors presented score 2, whereas most non-metastatic tumors showed score 1 (P < 0.001). Strong expression of BMPR-IA showed a statistically significant association with advanced clinical staging (P < 0.001) and high score of malignancy (P = 0.028).

CONCLUSIONS

The results of this study suggest that disturbances in the BMP-2 signaling pathway may be involved in the development of LLSCC and that the strong expression of BMPR-IA might be indicative of the development of metastasis in these lesions.

Polymorphisms in DNA damage response genes and head and neck cancer risk

BACKGROUND

Polymorphisms in DNA repair genes have been reported contributing factors in head and neck cancer risk but studies have shown conflicting results.

OBJECTIVE

To clarify the impact of DNA repair gene polymorphisms in head and neck cancer risk.

METHOD

A meta-analysis including 30 case-control studies was performed.

RESULTS

Marginally statistically significant association was found for XRCC1 codon 399 (for Caucasians only), XPD Asp312Asn and XRCC1 codon 194 variants and head and neck cancer.

CONCLUSION

Assessments of the effects of smoking, alcohol, human papillomavirus and race/ethnicity on the association between DNA repair gene polymorphisms and head and neck cancer are needed.

hMLH1 immunoexpression is related to the degree of epithelial dysplasia in oral leukoplakia

BACKGROUND

hMLH1 is a protein of the mammalian mismatch repair system responsible for genomic stability during repeated duplication. Relation between its altered expression linked to microsatellite instability has also been observed in oral leukoplakias (OL) and squamous cell carcinomas pointing to a possible role of hMLH1 in oral carcinogenesis. To our knowledge, this is the first study evaluating the immunoexpression of hMLH1 in OLs regarding their different degrees of epithelial dysplasia.

METHODS

Sixty-two specimens of OL were classified in four groups: 17 without dysplasia, 19 with mild dysplasia, 16 with moderate dysplasia, and 10 with severe dysplasia. Immunohistochemistry for hMLH1 was performed, and percentage of positive cells was assessed. In the statistical analysis, P values <0.005 were considered significant.

RESULTS

hMLH1 immunoexpression showed decreasing indexes from lesions with lower degrees of dysplasia to lesions with more severe dysplasia. Statistical difference was found mainly between suprabasal layers and total indexes.

CONCLUSIONS

hMLH1 immunoexpression was inversely related to the OL degree of dysplasia. The total epithelial hMLH1 index seems to be of more clinical relevance than the evaluation stratified by layers. Our findings also suggest a role of such alterations in this pathway of DNA repair as an early event in oral carcinogenesis.

Bone-invasive oral squamous cell carcinoma in cats: pathology and expression of parathyroid hormone-related protein

Feline oral squamous cell carcinoma (OSCC) is the most common oral tumor in cats. There is no effective treatment, and the average duration of survival after diagnosis is only 2 months. Feline OSCC is frequently associated with osteolysis; however, the mechanisms responsible are unknown. The objective of this study was to characterize the epidemiology and pathology of bone-invasive OSCC in cats and to determine the expression of select bone resorption agonists. In sum, 451 cases of feline OSCC were evaluated. There was no sex or breed predisposition, although there were more intact cats in the OSCC group compared to the control group. Gingiva was the most common site, followed by the sublingual region and tongue. Cats with lingual OSCC were younger (mean, 11.9 years) compared to cats with gingival OSCC (mean, 13.6 years). In addition to osteolysis, there was periosteal new bone formation, osseous metaplasia of tumor stroma, and direct apposition of OSCC to fragments of bone, suggestive of bone-binding behavior. Eighty-two cases were selected for immunohistochemical detection of parathyroid hormone-related protein (PTHrP). Specimens with osteolysis had increased PTHrP expression and nuclear localization, compared to OSCC without osteolysis. Thirty-eight biopsies of OSCC with osteolysis were evaluated for tumor necrosis factor α expression, and only 4 biopsies had such expression in a small proportion of tumor cells. Increased tumor expression of PTHrP and increased localization of PTHrP to the nucleus were associated with osteolysis and may play an important role in bone resorption and tumor invasion in cats with OSCC.

Oral cancer in Myanmar: a preliminary survey based on hospital-based cancer registries

The occurrence of oral cancer is not clearly known in Myanmar, where betel quid chewing habits are widely spread. Since betel quid chewing has been considered to be one of the important causative factors for oral cancer, the circumstantial situation for oral cancer should be investigated in this country. We surveyed oral cancer cases as well as whole body cancers from two cancer registries from Yangon and Mandalay cities, both of which have representative referral hospitals in Myanmar, and we showed that oral cancer stood at the 6th position in males and 10th in females, contributing to 3.5% of whole body cancers. There was a male predominance with a ratio of 2.1:1. Their most frequent site was the tongue, followed by the palate, which was different from that in other countries with betel quid chewing habits. About 90% of male and 44% of female patients had habitual backgrounds of chewing and smoking for more than 15 years. The results revealed for the first time reliable oral cancer frequencies in Myanmar, suggesting that longstanding chewing and smoking habits are etiological backgrounds for oral cancer patients.

Oral cancer: clinical features

Oral squamous cell carcinoma (OSCC) is a well-known malignancy that accounts for more than 90% of all oral cancers. In this article we will perform a brief review of its clinical characteristics and the differential diagnosis. Regarding symptoms, pain is the most frequent presentation and the tongue and the floor of the mouth have the highest occurrence. OSCC in its initial stages shows an erytholeukoplastic area without symptoms but in advanced stages there are ulcers and lumps with irregular margins which are rigid to touch. The different diagnosis should be established with other oral malignant diseases such as lymphomas, sarcomas and metastasis, which have rapid growth rates as opposed to the typical OSCC.