Cucurbitacin B induces ferroptosis in oral leukoplakia via the SLC7A11/mitochondrial oxidative stress pathway.

BACKGROUND: Oral leukoplakia (OLK), characterized by abnormal epithelial hyperplasia, is the most common precancerous oral mucosa lesion and is closely related to oxidative stress. Cucurbitacin B (CuB), a tetracyclic triterpenoid molecule derived from plants, has shown promising anti-proliferative and antioxidant effects in preclinical studies. However, whether CuB can play an antiproliferative role in OLK by regulating oxidative stress remains elusive. PURPOSE: To investigate the role of CuB in inhibiting the malignant progression of oral leukoplakia and to further explore its underlying mechanisms of action. METHODS: In vitro, the effect of CuB on the proliferation, migration, apoptosis, and cell cycle of OLK cells DOK was detected. The core genes and key pathways of OLK and CuB were analyzed in the transcriptome database, by using immunofluorescence, qRT-PCR, and Western blot to evaluate the expression levels of the ferroptosis markers ROS, GSH, MDA, Fe2+, and marker genes SLC7A11, GPX4, and FTH1. Immunohistochemistry of human tissue was performed to investigate the expression of the SLC7A11. In vivo, the model of OLK was established in C57BL/6 mice and the biosafety of CuB treatment for OLK was further evaluated. RESULTS: CuB substantially suppressed the proliferation of DOK cells. Bioinformatics analysis showed that the core targets of OLK crossing with CuB include SLC7A11 and that the essential pathways involve ROS and ferroptosis. In vitro experiments indicated that CuB might promote ferroptosis by down-regulating the expression of SLC7A11. We observed a gradual increase in SLC7A11 expression levels during the progression from normal oral mucosa to oral leukoplakia with varying degrees of epithelial dysplasia. In vivo experiments demonstrated that CuB inhibited the malignant progression of OLK by promoting ferroptosis in OLK mice and exhibited a certain level of biosafety. CONCLUSION: This study demonstrated for the first time that CuB could effectively inhibit the malignant progression of OLK by inducing ferroptosis via activating the SLC7A11/ mitochondrial oxidative stress pathway. These findings indicate that CuB could serve as the lead compound for the future development of anti-oral leukoplakia drugs.

Comparison of Effectiveness of Moringa Oleifera Leaves Extract Gel (2%) with Retino A (0.1%) Cream for Treatment of Oral Leukoplakia: Double Blinded Randomized Control Trial.

AIM: The study aims to evaluate and compare the efficacy of Moringa oleifera leaf extract gel (2%) & Retino A cream (0.1%) in reducing the size of lesions in oral leukoplakia. OBJECTIVES: The present study aimed to evaluate the efficacy of two interventions, Moringa oleifera mucoadhesive gel and Retino-A cream, in reducing the size of lesions in patients with oral leukoplakia. Specifically, the objectives were: (1) to assess the efficacy of Moringa oleifera mucoadhesive gel in determining the reduction in lesion size, (2) to assess the efficacy of Retino-A cream in determining the reduction in lesion size, and (3) to compare the efficacy of Moringa oleifera mucoadhesive gel (2%) in determining the change in lesion size in oral leukoplakia patients. METHODS: Clinically diagnosed cases of oral Leukoplakia were included in this study. The sample size is 72. Thirty-six patients had lesion sizes ranging from 2- 4 cm, and 36 patients had lesion sizes ranging from 4.1 - 6 cm that were equally distributed in the case and control groups using the chit system. The case and control groups had 36 patients with an equal size range of lesions. The case and control group participants will be advised topical application of the intervention and Retino-A thrice daily using a sterile cotton bud. RESULTS: M. oleifera gel (2%) was found to be more effective in the reduction in the size of the lesion as compared to Retino-A in the treatment of oral leukoplakia patients. CONCLUSION: This study showed that M. oleifera mucoadhesive gel (2%) is an effective and safe treatment option for oral leukoplakia patients. It demonstrated a significant reduction in lesion size compared to Retino-A cream (0.1%) after 3 months of therapy, without any reported adverse effects. However, long-term follow-up studies are needed to evaluate its long-term effectiveness. The potent antioxidant property of M. oleifera makes it a promising candidate for further studies with concentration variations and in other potentially malignant oral disorders, such as lichen planus and OSMF. The development of chemotherapeutic drugs from M. oleifera for cancer treatment should also be considered. Overall, M. oleifera appears to be a promising natural alternative to synthetic drugs for the treatment of oral leukoplakia. KEY WORDS: Leukoplakia, Oral leukoplakia, premalignant lesion, precancer, potentially malignant disorders.

Eficacia clínica de la terapia fotodinámica por 5-ALA tópico en el manejo onco-preventivo de lesiones de leucoplasia oral. Una revisión sistemática / Clinical efficacy of topical 5-ALA photodynamic therapy in the onco-preventive management of oral leukoplakia lesions. A systematic review

Objetivo: La leucoplasia oral es el desorden maligno de la mucosa bucal más prevalente a nivel global y su manejo clínico sigue siendo un desafío. Se llevó a cabo una revisión sistemática para determinar la eficacia clínica de la terapia fotodinámica mediada por ácido 5-aminolevulínico tópico como una alternativa de quimio-prevención para las diferen- tes formas clínicas de la leucoplasia oral. Materiales y métodos: Empleando términos MeSH, se realizó una búsqueda exhaustiva en diferentes bases digi- tales de ensayos clínicos publicados en inglés en los últimos 30 años acerca del uso de la terapia fotodinámica mediada por ácido 5-aminolevulínico tópico como fotosensibilizador, y radiación láser de baja intensidad o luz LED como posibles fuentes de iluminación. Resultados: La revisión sistematizada que aplicó la guía PRISMA mostró una eficacia del 88,6% para este modo de fototerapia en el manejo de leucoplasias orales, con un 60,7% de respuesta completa y 27,9% de respuesta parcial. Además, el tamaño de efecto fue mayor para las formas clíni- cas homogéneas con cambios displásicos, independientemen- te del tipo de fuente de luz. La ausencia de respuesta fue del 11,4%, pero la evidencia empleada en este análisis fue mo- derada. Conclusión: La terapia fotodinámica mediada por áci- do 5-aminolevulínico tópico parece ser una alternativa útil en el manejo onco-preventivo de lesiones de leucoplasia oral. Sin embargo, es recomendable ejecutar ensayos clínicos controla- dos y aleatorizados con metodologías homogéneas que per- mitan generar un meta-análisis con un alto nivel de evidencia

Aim: Oral leukoplakia is globally the most prevalent ma- lignant disorder of the oral mucosa and its clinical manage- ment remains a challenge. A systematic review was carried out to determine the clinical efficacy of photodynamic therapy mediated by topical 5-aminolevulinic acid as an alternative for chemoprevention in the different clinical forms of oral leu- koplakia. Materials and methods: Using MeSH terms, an ex- haustive search was carried out in different digital databases of clinical trials published in English in the last 30 years on the use of photodynamic therapy mediated by topical 5-ami- nolevulinic acid as a photosensitizer, and low-intensity laser radiation or LED light as possible lighting sources. Results: The systematized review using PRISMA guide- lines showed an efficacy of 88.6% for this mode of photother- apy in the management of oral leukoplakias, based on 60.7% of complete response and 27.9% of partial response. In addi- tion, the effect size was larger in homogeneous clinical forms with dysplastic changes, regardless of the type of light source. There was an 11.4% of absence of response, but the evidence used in this analysis was moderate. Conclusion: Photodynamic therapy mediated by topical 5-aminolevulinic acid seems to be a useful alternative in the onco-preventive management of oral leukoplakia lesions. However, it is recommendable to perform controlled and ran- domized clinical trials with homogeneous methodologies that allow the generation of a meta-analysis with a high level of evidence (AU)

Plum-blossom needle assisted photodynamic therapy for the treatment of oral potentially malignant disorder in the elderly.

Oral leukoplakia (OLK) is one of the most common oral potentially-malignant disorders (OPMD) with complex causes, a long disease course and a high tendency for recrudescence. Although a variety of methods exist for treating this disease, canceration rates remain high. Herein, we described a case of 72-year-old male patient with OLK of the palatine mucous membrane who had achieved complete remission after being treated with five sessions of plum-blossom needle (PBN) assisted 5-aminolevulinic acid-photodynamic therapy (ALA-PDT). The patient had since been subsequently placed under close observation (>12 mo). To date, there has been no recurrence. PBN assisted PDT might be suitable for the treatment of OPMDs in patients presenting with epithelial hyperkeratosis.

Effects of Black Raspberry Extract and Berry Compounds on Repair of DNA Damage and Mutagenesis Induced by Chemical and Physical Agents in Human Oral Leukoplakia and Rat Oral Fibroblasts.

Black raspberries (BRB) have been shown to inhibit carcinogenesis in a number of systems, with most studies focusing on progression. Previously we reported that an anthocyanin-enriched black raspberry extract (BE) enhanced repair of dibenzo-[a,l]-pyrene dihydrodiol (DBP-diol)-induced DNA adducts and inhibited DBP-diol and DBP-diolepoxide (DBPDE)-induced mutagenesis in a lacI rat oral fibroblast cell line, suggesting a role for BRB in the inhibition of initiation of carcinogenesis. Here we extend this work to protection by BE against DNA adduct formation induced by dibenzo-[a,l]-pyrene (DBP) in a human oral leukoplakia cell line (MSK) and to a second carcinogen, UV light. Treatment of MSK cells with DBP and DBPDE led to a dose-dependent increase in DBP-DNA adducts. Treatment of MSK cells with BE after addition of DBP reduced levels of adducts relative to cells treated with DBP alone, and treatment of rat oral fibroblasts with BE after addition of DBPDE inhibited mutagenesis. These observations showed that BE affected repair of DNA adducts and not metabolism of DBP. As a proof of principle we also tested aglycones of two anthocyanins commonly found in berries, delphinidin chloride and pelargonidin chloride. Delphinidin chloride reduced DBP-DNA adduct levels in MSK cells, while PGA did not. These results suggested that certain anthocyanins can enhance repair of bulky DNA adducts. As DBP and its metabolites induced formation of bulky DNA adducts, we investigated the effects of BE on genotoxic effects of a second carcinogen that induces bulky DNA damage, UV light. UV irradiation produced a dose-dependent increase in cyclobutanepyrimidine dimer levels in MSK cells, and post-UV treatment with BE resulted in lower cyclobutanepyrimidine dimer levels. Post-UV treatment of the rat lacI cells with BE reduced UV-induced mutagenesis. Taken together, the results demonstrate that BE extract reduces bulky DNA damage and mutagenesis and support a role for BRB in the inhibition of initiation of carcinogenesis.

Chemoprevention of oral cancer in leukoplakia patients: A systematic review and meta-analysis.

The systematic review and meta-analysis of published randomised controlled trials (RCTs) was conducted to review the effectiveness of current chemopreventive agents in the treatment of oral leukoplakia lesions (OPLs) and prevention of their progression to oral cancer. Material was identified through a retrospective literature search of the electronic PubMed database, Embase and Cochrane Library between 2008 and 2016.Eight RCTs were included for systematic review. The pooled estimate showed a 14% greater chance of responding for those randomised to interventions compared with placebo (Risk Ratio [RR] 1.14, 95% confidence interval [CI] 0.72 to 1.81). The CI from individual studies overlapped. The results suggested that there were no significant differences in comparing clinical responses between chemopreventive agents with placebo in treatment of OPLs. It is time to investigate new agents for oral cancer chemoprevention.

A Randomized Double-Blind Placebo-Controlled Phase IIB Trial of Curcumin in Oral Leukoplakia.

Oral leukoplakia is a potentially malignant lesion of the oral cavity, for which no effective treatment is available. We investigated the effectiveness of curcumin, a potent inhibitor of NF-κB/COX-2, molecules perturbed in oral carcinogenesis, to treat leukoplakia. Subjects with oral leukoplakia (n = 223) were randomized (1:1 ratio) to receive orally, either 3.6 g/day of curcumin (n = 111) or placebo (n = 112), for 6 months. The primary endpoint was clinical response obtained by bi-dimensional measurement of leukoplakia size at recruitment and 6 months. Histologic response, combined clinical and histologic response, durability and effect of long-term therapy for an additional six months in partial responders, safety and compliance were the secondary endpoints. Clinical response was observed in 75 (67.5%) subjects [95% confidence interval (CI), 58.4-75.6] in the curcumin and 62 (55.3%; 95% CI, 46.1-64.2) in placebo arm (P = 0.03). This response was durable, with 16 of the 18 (88.9%; 95% CI, 67.2-96.9) subjects with complete response in curcumin and 7 of 8 subjects (87.5%) in placebo arm, demonstrating no relapse after 6 months follow-up. Difference in histologic response between curcumin and placebo was not significant (HR, 0.88, 95% CI, 0.45-1.71; P = 0.71). Combined clinical and histologic response assessment indicated a significantly better response with curcumin (HR, 0.50; 95% CI, 0.27-0.92; P = 0.02). Continued therapy, in subjects with partial response at 6 months, did not yield additional benefit. The treatment did not raise any safety concerns. Treatment of oral leukoplakia with curcumin (3.6 g for six months), thus was well tolerated and demonstrated significant and durable clinical response for 6 months. Cancer Prev Res; 9(8); 683-91. ©2016 AACR.

Treatment of oral leukoplakia with a low-dose of beta-carotene and vitamin C supplements: a randomized controlled trial.

Management of oral leukoplakia-a potentially malignant disorder-is currently not evidence-based. Of the few randomized trials that have been reported, most have negative data. Therefore, a multi-centre, randomized, double-blind controlled trial (RCT) was undertaken to evaluate the use of low-dose beta-carotene combined with vitamin C supplements for the treatment and to prevent malignant transformation of oral leukoplakia. 46 Japanese participants with oral leukoplakia were allocated randomly either to an experimental arm (10 mg day(-1) of beta-carotene and 500 mg day(-1) of vitamin C) or placebo arm (50 mg day(-1) of vitamin C). Current or ex-smokers within 3 months of cessation were excluded. The supplements were continued over a period of 1 year. The primary endpoint was clinical remission at 1-year and the likelihood of malignant transformation during a 5-year follow-up period as a secondary endpoint. The overall clinical response rate in the experimental arm was 17.4% (4/23) and 4.3% (1/23) in the placebo arm (p = 0.346). During the median 60-month follow-up period, two subjects in the experimental arm and three in the control arm developed oral cancer. Under the intention-to-treat principle, relative risk by supplementing with beta-carotene and vitamin C was 0.77 (95%CI: 0.28-1.89) (p = 0.580) by the Cox proportional hazards model. No unfavorable side-effects were noted. Beta-carotene (10 mg day(-1) ) and vitamin C were neither effective for clinical remission, nor for protection against the development of cancer. Data from this RCT does not support the hypothesis that chemoprevention with this treatment is effective for oral leukoplakia.

Biopolymeric film containing bioactive naphthoquinone (shikonin) in combined therapy of inflammatory destructive lesions in the buccal mucosa.

Clinical morphological efficiency of local application of a new biopolymeric film was studied. The film was based on methylcellulose derivatives and contained shikonin (preparation of plant origin) and its esters isolated from Lithospermum erythrorhizon L. cell culture. Combined therapy of 30 patients (34-72 years) with erosive ulcerative lichen planus and leukoplakia of the buccal mucosa was carried out. Local application of the new drug led to more rapid pain relief, epithelialization of the inflammatory destructive foci in the buccal mucosa, and reduced the intensity of morphological signs of lesions in the studied patient population.

Photodynamic therapy outcome for oral dysplasia.

INTRODUCTION: Photodynamic therapy (PDT) is a minimally invasive surgical intervention used in the management of tissue disorders. It can be applied before, or after, any of the conventional modalities, without compromising these treatments or being compromised itself. MATERIALS AND METHODS: In this prospective study, a total of 147 consecutive patients with oral potentially malignant disorders were treated with surface illumination PDT, using 5-ALA or mTHPC as the photosensitizer. The average age was 53 ± 8.9 years. The patients' recovery was uneventful and no complications reported. Comparisons with the clinical and histopathological features and rate of recurrence as well as malignant transformation were made. The patients were followed-up for a mean of 7.3 years. ANALYSIS AND RESULTS: Homogenous leukoplakias were identified in 55 patients, non-homogenous leukoplakias in 73 patients, whereas 19 patients had erythroplakias. Ex- and current lifelong smokers formed 84.4% of the recruited patients. While people who currently smoke and drink formed 38.1% (56 patients) of the cohort. Erythroplakias were mainly identified in heavy lifelong smokers. The most common identified primary anatomical locations were the lateral border of tongue, floor of mouth and retromolar area. Moderate dysplasia was identified in 33 patients while 63 patients had severe dysplasias; and 32 patients had a histopathological diagnosis of carcinoma in situ. The rate of recurrence in laser surgery was approximately 11.6%. Malignant transformation was observed in 11 patients (7.5%), in the tongue, floor of mouth and retromolar area. Recurrence and malignant transformation was mainly identified in erythroplakias and non-homogenous leukoplakias. The final outcome of the cohort showed that 11 (7.5%) suffered from progressive disease, 5 (3.4%) had stable disease, 12 (8.2%) were considered partially responsive to the therapy. Complete response was identified in 119/147 patients (81%). CONCLUSION: 5-ALA-PDT and/or mTHPC-PDT offer an effective alternative treatment for oral potentially malignant disorders.

Lycopene: features and potential significance in the oral cancer and precancerous lesions.

Data from epidemiological studies have indicated that diets rich in fruits and vegetables are likely to benefit many aspects of the prevention of oral malignancy. Lycopene is a red-coloured carotenoid predominantly accumulated in tomatoes as well as other fruits and vegetables. It has been claimed to alleviate chronic diseases such as cancers and cardiovascular disease. Hence, the aim of this review is to summarize the features and its potential significance of lycopene in the development, prevention and treatment of oral premalignant lesions and oral cancer. Studies showed that lycopene might have beneficial effects in the management of some premalignant lesions in the oral cavity including oral submucous fibrosis and oral leukoplakia and may be an adjunct in the prevention and therapy of oral cancer. However, more mechanistic studies and randomized controlled trials of large sample size are necessary to further confirm these effects and to eventually make lycopene to be used in the community prevention and clinically routine management of these diseases.

Topical photodynamic therapy is very effective for oral verrucous hyperplasia and oral erythroleukoplakia.

BACKGROUND: Oral verrucous hyperplasia (OVH) and oral erythroleukoplakia (OEL) are two oral precancerous lesions with relatively high malignant transformation potential. One of the best cancer prevention strategies is to use a conservative and effective treatment modality to eliminate oral precancers to stop their further malignant transformation. Our previous studies have shown that the topical 5-aminolevulinic acid-mediated photodynamic therapy (topical ALA-PDT) using the 635-nm light-emitting diode (LED) light is very effective for OVH and OEL lesions. METHODS: Because the laser machine is a more-popular light source than the LED device in PDT clinics, in this study 40 OVH and 40 OEL lesions were treated once a week with the same PDT protocol but using the 635-nm laser light to evaluate whether this laser light-mediated topical ALA-PDT was also effective for OVH and OEL lesions. RESULTS: We found that all the 40 OVH lesions exhibited complete response (CR) after an average of 3.6 PDT treatments. Of the 40 OEL lesions, 38 showed CR after an average of 3.4 PDT treatments and two showed partial response (PR). Better PDT outcomes were significantly associated with OVH and OEL lesions with the smaller size, pink to red color, epithelial dysplasia, or thinner surface keratin layer. CONCLUSION: This study indicates that the laser light-mediated topical ALA-PDT is also very effective for OVH and OEL lesions. Therefore, we suggest that topical ALA-PDT using either the LED or laser light may serve as the first-line treatment of choice for OVH and OEL lesions.

Possible action mechanism for curcumin in pre-cancerous lesions based on serum and salivary markers of oxidative stress.

Extensive research within the past half-century has indicated that curcumin (diferuloylmethane), a yellow pigment in curry powder, exhibits anti-oxidant, anti-inflammatory, and pro-apoptotic activities. We investigated whether the anti-pre-cancer activities assigned to curcumin are mediated through an anti-oxidant and DNA-protecting mechanism. Patients with oral leukoplakia, oral submucous fibrosis or lichen planus, and healthy individuals (n = 25 for each group) aged 17-50 years were selected. Salivary and serum oxidative markers such as malonaldehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), vitamins C and E were measured just prior to the intake of curcumin, after one week of curcumin intake and following clinical cure of precancerous lesions. Serum and salivary vitamins C and E showed increases, while MDA and 8-OHdG levels showed decreases in patients with oral leukoplakia, submucous fibrosis and lichen planus after intake of curcumin for all categories of precancerous lesions. The changes in these values were observed to be statistically significant after clinical cure of the disease (P < 0.05). The five-point rating scale for pain, as well as lesion size in oral leukoplakia, submucous fibrosis and lichen planus, improved significantly (P < 0.05). In addition, in submucous fibrosis, mouth opening (P < 0.05) recovered significantly. In oral leukoplakia, submucous fibrosis and lichen planus, the levels of serum and salivary vitamins C and E increased significantly, while MDA and 8-OHdG levels decreased after 131(15), 211(17), and 191(18) days, respectively. Values for serum and salivary vitamins C and E showed a significant decrease in oral leukoplakia, submucous fibrosis and lichen planus, in contrast to healthy individuals, but increased significantly in all groups subsequent to curcumin administration after clinical cure of lesions. Based on these results, we can conclude that curcumin mediates its anti-pre-cancer activities by increasing levels of vitamins C and E, and preventing lipid peroxidation and DNA damage.

High-dose fenretinide in oral leukoplakia.

We previously showed that low-dose fenretinide (200 mg/d) had limited activity in retinoid-resistant oral leukoplakia (34% response rate) possibly because serum drug levels were insufficient to induce retinoid receptor-independent apoptosis. Therefore, we designed the single-arm phase II trial reported here to investigate whether higher-dose fenretinide would improve leukoplakia response over that of our previous study. Leukoplakia patients received fenretinide (900 mg/m(2) twice daily) in four 3-week cycles (1 week on drug followed by 2 weeks off). At week 12, clinical responses were determined and blood samples were collected for serum drug level assessments. A planned interim futility analysis led to early trial closure after the initial 15 (of 25 planned) patients because only 3 (20%) had a partial response (stopping rule:

Black tea (Camellia sinensis) as a chemopreventive agent in oral precancerous lesions.

Oral carcinoma is the most common malignancy found in adult Indian men and the third most common in adult Indian women. About half of all cases are found to be associated with precancerous lesions, chiefly leukoplakia. We wanted to explore the possible benefits of black tea (Camellia sinensis) administered to patients with oral leukoplakia. Eighty-two subjects with oral leukoplakia underwent micronuclei and chromosomal assays on exfoliated oral mucosal epithelium, after which they received black tea in a fixed regimen. The micronuclei assay was repeated at 6 months, and the chromosomal study at 1 year. After the first year, the first 15 patients entered onto this study showed a significant decrease in the micronuclei frequency and chromosomal aberrations, which correlated with the clinical improvement. Several in vitro and animal studies have suggested the efficacy of tea in the chemoprevention of cancer. To the best of our knowledge, this is the first report on the effect of black tea in oral leukoplakia.

[Improving the efficiency of combined therapy of patients with leukoplakia of the buccal mucosa using Phytomix-40 combined plant preparation]. / Vozmozhnosti povysheniia éffektivnosti kompleksnogo lecheniia bol'nykh leikoplakiei slizistoi obolochki polosti rta pri ispol'zovanii kompleksnogo rastitel'nogo preparata Fitomiks-40.

Today leukoplakia of the buccal mucosa is regarded as a typical pre-tumorous condition, both in medicine in general and in dentistry, in particular. Leukoplakia is in fact resistant to conservative treatment, and therefore search for new approaches to therapy of this disease is a pressing problem. Phytomix-40 (PM-40) is a mixture of natural extracts of 40 medicinal plants developed for practical oncology. PM was used in combined therapy of patients with leukoplakia with good results.

Systematic review of randomized trials for the treatment of oral leukoplakia.

Oral leukoplakia is a relatively common oral lesion that, in a varying proportion of cases, undergoes malignant transformation. The aim of this review was to assess the effectiveness of treatments for leukoplakia. Randomized controlled trials (RCTs) enrolling patients with a diagnosis of oral leukoplakia were identified by searching biomedical databases, hand-searching relevant oral medicine journals, and contacting oral medicine experts through a European mailing list. The methodological quality of included studies was assessed on the basis of the method of allocation concealment, blindness of the study, and loss of participants. Data were analyzed by calculating relative risk. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. Six RCTs were included in the review. Vitamin A and retinoids were tested in four RCTs; the other agents tested were bleomycin, mixed tea, and beta carotene. Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with placebo. Treatment with beta carotene and vitamin A or retinoids was associated with better rates of clinical remission, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients since drop-out rates were similar between treatment and control groups. It is noteworthy that the possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has apparently never been studied by means of an RCT. To date, in conclusion, there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion; however, relapses and adverse effects are common.

Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions.

Curcumin (diferuloylmethane), a yellow substance from the root of the plant Curcuma longa Linn., has been demonstrated to inhibit carcinogenesis of murine skin, stomach, intestine and liver. However, the toxicology, pharmacokinetics and biologically effective dose of curcumin in humans have not been reported. This prospective phase-I study evaluated these issues of curcumin in patients with one of the following five high-risk conditions: 1) recently resected urinary bladder cancer; 2) arsenic Bowen's disease of the skin; 3) uterine cervical intraepithelial neoplasm (CIN); 4) oral leucoplakia; and 5) intestinal metaplasia of the stomach. Curcumin was taken orally for 3 months. Biopsy of the lesion sites was done immediately before and 3 months after starting curcumin treament. The starting dose was 500 mg/day. If no toxicity > or = grade II was noted in at least 3 successive patients, the dose was then escalated to another level in the order of 1,000, 2,000, 4,000, 8,000, and 12,000 mg/day. The concentration of curcumin in serum and urine was determined by high pressure liquid chromatography (HPLC). A total of 25 patients were enrolled in this study. There was no treatment-related toxicity up to 8,000 mg/day. Beyond 8,000 mg/day, the bulky volume of the drug was unacceptable to the patients. The serum concentration of curcumin usually peaked at 1 to 2 hours after oral intake of crucumin and gradually declined within 12 hours. The average peak serum concentrations after taking 4,000 mg, 6,000 mg and 8,000 mg of curcumin were 0.51 +/- 0.11 microM, 0.63 +/- 0.06 microM and 1.77 +/- 1.87 microM, respectively. Urinary excretion of curcumin was undetectable. One of 4 patients with CIN and 1 of 7 patients with oral leucoplakia proceeded to develop frank malignancies in spite of curcumin treatment. In contrast, histologic improvement of precancerous lesions was seen in 1 out of 2 patients with recently resected bladder cancer, 2 out of 7 patients of oral leucoplakia, 1 out of 6 patients of intestinal metaplasia of the stomach, I out of 4 patients with CIN and 2 out of 6 patients with Bowen's disease. In conclusion, this study demonstrated that curcumin is not toxic to humans up to 8,000 mg/day when taken by mouth for 3 months. Our results also suggest a biologic effect of curcumin in the chemoprevention of cancer.

Initial experience in the treatment of oral leukoplakia with high-dose vitamin A and follow-up 5-aminolevulinic acid induced protoporphyrin IX fluorescence.

The aim of photodynamic diagnostics is complete visualization of all neoplastic lesions in a tumorous organ after the application of a tumor-selective photosensitizer. We explored the potential benefit of a combination of retinyl palmitate for the treatment of oral leukoplakias and follow-up diagnosis of malignant tissue by using 5-aminolevulinic acid (5-ALA) as a fluorescence marker. Semiquantitative measurements were performed following the topical application of 5-ALA in six patients. After biopsy and histological evaluation of tissue specimens the patients were treated with escalating doses of retinyl palmitate. After treatment periods ranging from 4 to 8 weeks 5-ALA was again applied for photodetection of persisting fluorescence. In all cases prior to retinyl palmitate treatment a prominent red fluorescence indicated tissue dysplasia. Eight weeks after treatment with retinyl palmitate decreased red fluorescence intensities were found, and repeated histological evaluations showed no persistent signs of dysplastic lesions. Our initial experience shows that high doses of retinyl palmitate can be useful for treating dysplastic lesions in the upper aerodigestive tract and can be monitored with 5-ALA induced protoporphyrin IX fluorescence.

Predicting cancer development in oral leukoplakia: ten years of translational research.

Our 10-year translational study of the oral premalignant lesion (OPL) model has advanced the basic understanding of carcinogenesis. Although retinoids have established activity in this model, a substantial percentage of our OPL patients progress to cancer, especially after treatment is stopped. On the basis of our 10-year OPL study, we have developed the first comprehensive tool for assessing cancer risk of OPL patients. This cancer risk assessment tool incorporates medical/demographic variables, epidemiological factors, and cellular and molecular biomarkers. Between 1988 and 1991, 70 advanced OPL patients were enrolled in a chemoprevention trial of induction with high dose isotretinoin (1.5 mg/kg/day for 3 months) followed by 9 months of maintenance treatment with either low dose isotretinoin (0.5 mg/kg/day) or beta-carotene (30 mg/d; total treatment duration, 1 year). We assessed the relationship between cancer risk factors and time to cancer development by means of exploratory data analysis, logrank test, Cox proportional hazard model, and recursive partitioning. With a median follow-up of 7 years, 22 of our 70 patients (31.4%) developed cancers in the upper aerodigestive tract following treatment. The overall cancer incidence was 5.7% per year. The most predictive factors of cancer risk are OPL histology, cancer history, and three of the five biomarkers we assessed (chromosomal polysomy, p53 protein expression, and loss of heterozygosity at chromosome 3p or 9p). In the multivariable Cox model, histology (P = 0.0003) and the combined biomarker score of chromosomal polysomy, p53, and loss of heterozygosity (P = 0.0008) are the strongest predictors for cancer development. Retinoic acid receptor beta and micronuclei were not associated with increased cancer risk. We have demonstrated a successful strategy of comprehensive cancer risk assessment in OPL patients. Combining conventional medical/demographic variables and a panel of three biomarkers can identify high risk patients in our sample. This result will need to be validated by future studies. With the identification of high risk individuals, more efficient chemoprevention trials and molecular targeting studies can be designed.