Native fluorescence spectroscopic evaluation of chemotherapeutic effects on malignant cells using nonnegative matrix factorization analysis.

The native fluorescence spectra of retinoic acid (RA)-treated and untreated human breast cancerous cells excited with the selective wavelengths of 300 nm and 340 nm were measured and analyzed using a blind source separation method namely Nonnegative Matrix Factorization (NMF). The results show that the fluorophores of human malignant breast cells change their compositions when they are treated with RA. The reduced contribution from tryptophan, NADH and flavin to the fluorescence of the treated breast cancerous cells was observed in comparison with that of the untreated cells. The results indicate that the decrease of adenosine triphosphate (ATP) in the RA-treated cells. The possible clinical applications of this native fluorescence study are discussed.

Pilot study using SELDI-TOF-MS based proteomic profile for the identification of diagnostic biomarkers of thyroid proliferative diseases.

Biomarkers for thyroid cancer (TCa) lack specificity. To develop TCa specific biomarkers, SELDI-TOF-MS was used to examine the proteomic profile of biopsies obtained from papillary TCa along with adjacent normal tissue. Sixty-three potential biomarkers were categorized by univariate analysis into single biomarker candidates and segregated by multivariate analysis into normal and cancerous groups. Our studies demonstrate the sensitivity and reproducibility of this approach to detect biomarkers for TCa.

A simple method for fixation and microdissection of frozen fresh tissue sections for molecular cytogenetic analysis of cancers.

Microdissection has been widely used for procuring DNA from specific microscopic regions of formalin fixed, paraffin embedded tissue sections. We have developed a method for fixation and microdissection of frozen fresh biopsy tissue sections. Five micrometer frozen fresh tissue sections were fixed with ethanol and stored at room temperature. Well defined regions from hematoxylin and eosin (H & E) stained or unstained sections were briefly steamed and microdissected using a needle. The dissected tissue was digested with proteinase K and DNA was isolated. Whole genome amplifications were obtained by degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) from these samples. The reliability of this technique was demonstrated by comparing conventional comparative genomic hybridization (CGH) with DOP-PCR-CGH. The advantages of this method are that frozen fresh sections can be fixed easily and stored for more than 4 years, it is easy to microdissect and pick-up very minute regions (0.1 mm(2)), and it is rapid; microdissection and purification can be accomplished within 3 h. Using DNA from microdissected sections, DOP-PCR-CGH revealed genetic abnormalities more accurately than conventional CGH. Although this novel method was demonstrated using DOP-PCR-CGH, we believe that it will be useful for other genetic analyses of specific small regions and cell populations. We also observed whether storage time, H & E staining and crude DNA extracts affected the quality of amplified DNA. DNA integrity was maintained for at least 49 months in ethanol fixed sections that were stored at room temperature, but DNA was gradually degraded after one month if the ethanol fixed sections had been H & E stained and stored. When crude DNA extracts from H & E stained sections were used, the size of the DOP-PCR product was reduced. Our study suggests that ethanol fixed tissue sections may be stored at room temperature for at least 4 years without DNA degradation, the H & E stains may not affect the quality of amplified DNA, but H & E or other components in the staining process may reduce the size of DOP-PCR product, which is critical for the quality of CGH hybridization.

Tobacco carcinogen-detoxifying enzyme UGT1A7 and its association with orolaryngeal cancer risk.

BACKGROUND: UDP-glucuronosyltransferase 1A7 (UGT1A7) detoxifies several tobacco carcinogens. We determined whether UGT1A7 expression is observed in normal orolaryngeal tissue and whether UGT1A7 allelic variations are associated with the risk for orolaryngeal cancer. METHODS: UGT1A7 expression in normal orolaryngeal tissue was determined by semiquantitative reverse transcription-polymerase chain reaction (PCR). Buccal cell DNA isolated from 194 case subjects with orolaryngeal cancer and from 388 control subjects who were matched by sex, age, and race was subjected to UGT1A7 genotyping with the use of combined PCR-restriction fragment length polymorphism and allelic discrimination analysis. All statistical tests were two-sided. RESULTS: UGT1A7 messenger RNA was expressed at similar levels in the esophagus, tongue, tonsil, floor of the mouth, and larynx. Genotyping revealed the presence of three variant reduced-activity UGT1A7 alleles in both Caucasians and African-Americans. Individuals with any of the predicted low-activity UGT1A7 genotypes had an increased risk of orolaryngeal cancer (odds ratio [OR] = 3.7; 95% confidence interval [CI] = 1.7 to 8.7) relative to subjects with the wild-type genotype. Both Caucasians and African-Americans with the low-activity genotypes had statistically significantly increased orolaryngeal cancer risk compared with Caucasians and African-Americans with the wild-type genotype (OR = 2.8 [95% CI = 1.1 to 7.6] and OR = 6.2 [95% CI = 1.2 to 31], respectively). For subjects with the predicted low-activity genotypes, the risks of oral cavity cancer (OR = 4.2; 95% CI = 1.7 to 10) and laryngeal cancer (OR = 3.7; 95% CI = 0.99 to 14) were similar. There was no association between UGT1A7 genotype and orolaryngeal cancer risk in never smokers, whereas subjects with predicted low-activity UGT1A7 genotypes who were light smokers (OR = 3.7; 95% CI = 1.1 to 12) or heavy smokers (OR = 6.1; 95% CI = 1.5 to 25) had an increased risk. CONCLUSIONS: The tissue expression of UGT1A7 is consistent with the possibility of a physiologic role in orolaryngeal cancer. Variations in the UGT1A7 gene that reduce UGT1A7 activity may affect the risk of smoking-related orolaryngeal cancer.

Elucidation of CYP2E1 5' regulatory RsaI/Pstl allelic variants and their role in risk for oral cancer.

The CYP2E1 gene, whose protein product plays an important role in the metabolism of various carcinogens, exhibits two polymorphisms recognized by the restriction enzymes RsaI and PstI in its transcriptional regulatory region that have been previously implicated in cancer susceptibility. In this study, we have examined these polymorphisms to elucidate CYP2E1 allelic haplotype, examining the prevalence of these CYP2E1 alleles in Caucasians and African Americans and their potential role in risk for oral cancer. In addition to the c1 (RsaI[+]/PstI[-]) and c2 (RsaI[-]/PstI[+]) alleles reported in previous studies, we have identified two new alleles, c3 (RsaI[+]/PstI[+]) and c4 (RsaI[-]/PstI[-]). The prevalence of the c2 and c3 alleles differs between racial groups, with African Americans exhibiting a lower prevalence of the c2 allele (0.003) but a higher prevalence of the c3 allele (0.049) than Caucasians (0.031 for c2 and 0.004 for c3). Of the 570 subjects screened in this study, the c4 allele was observed in one subject, a Caucasian case with the (c4/c4) genotype. A significant increase in the CYP2E1 (c1/c1) genotype was observed in oral cancer cases as compared to frequency-matched controls in subjects who smoked < or =24 pack-years (P=0.033). No association was observed between CYP2E1 genotype and risk for oral cancer in the heavy-smoking group (i.e. > 24 pack-years). Similar trends were observed for both Caucasians and African Americans. These data suggest that the c1 allele may contribute to increased risk for oral cancer.

Estrogen metabolism as a risk factor for head and neck cancer.

OBJECTIVE: Estrogen metabolites have been associated in the pathogenesis of breast and cervical cancer; 16alpha-hydroxyestrone(16alpha-OHE1) demonstrated proliferative effects whereas 2-hydroxyestrone(2-OHE1) had antiproliferative effects. Our study's objective is to demonstrate that head and neck (H&N) cancer patients metabolize estrogen differently than healthy controls, which may constitute a risk factor for H&N cancer development. STUDY DESIGN: Urinary metabolite levels of 2-OHE1 and 16alpha-OHE1 from 50 H&N cancer patients and 50 age- and sex-matched controls were measured using enzyme-linked immunosorbent assay (ELISA). Absolute values and 2-/16alpha-OHE1 ratios were calculated. Conditional logistic regression for univariate and multivariate analysis with odds ratio (OR) and 95% confidence interval (CI) were used. RESULTS: Thirty percent (15 of 50) from the case group had a low 2-/16alpha-OHE1 ratio compared with only 4% (2 of 50) in the control group (OR = 11.1; 1.4-91.5, 95% CI) (P < 0.05). When adjusted for tobacco, OR remained significant at 15.6 (1.1-212.5, 95% CI) (P < 0.05). CONCLUSION: H&N cancer patients are more likely to express abnormal estrogen metabolism than healthy controls; 2-/16alpha-OHE1 may serve as a potential biological marker of individuals at increased risk of H&N cancer.

Environmental tobacco smoking, mutagen sensitivity, and head and neck squamous cell carcinoma.

Although active tobacco smoking has been considered a major risk factor for head and neck cancer, few studies have evaluated environmental tobacco smoke (ETS) and its interaction with mutagen sensitivity on the risk of head and neck cancer. We investigated the relationship between ETS and head and neck cancer in a case-control study of 173 previously untreated cases with pathologically confirmed diagnoses of squamous cell carcinoma of the head and neck and 176 cancer-free controls at Memorial Sloan-Kettering Cancer Center between 1992 and 1994. A structured questionnaire was used to collect ETS exposure and other covariates including a history of active tobacco smoking and alcohol use. ETS measures include a history of ETS exposure at home and at workplace. The associations between passive smoking and head and neck cancer were analyzed by Mantel-Haenszel methods and logistic regression models. Additive and multiplicative models were used to evaluate effect modifications between ETS and mutagen sensitivity. The crude odds ratio (OR) for ETS exposure was 2.8 [95% confidence intervals (CI), 1.3-6.0]. Controlling for age, sex, race, education, alcohol consumption, pack-years of cigarette smoking, and marijuana use, the risk of squamous cell carcinoma of the head and neck was increased with ETS (adjusted OR, 2.4; 95% CI, 0.9-6.8). Dose-response relationships were observed for the degree of ETS exposure; the adjusted ORs were 2.1 (95% CI, 0.7-6.1) for those with moderate exposure and 3.6 (95% CI, 1.1-11.5) for individuals with heavy exposure (P for trend = 0.025), in comparison with those who never had ETS exposures. These associations and the dose-response relationships were still present when the analysis was restricted to nonactive smoking cases and controls (crude OR, 2.2; 95% CI, 0.6-8.4). Crude odds ratios were 1.8 for those with moderate ETS exposure and 4.3 for individuals with heavy ETS exposure among nonsmoking cases and controls (P for trend = 0.008). More than multiplicative interaction was suggested between passive smoking and mutagen sensitivity. This study suggests that ETS exposure may increase the risk of head and neck cancer with a dose-response pattern. Our analysis indicated that passive smoking may interact with mutagen sensitivity and other risk factors to increase the risk of head and neck cancer. Our results need to be interpreted with caution because of potential residual confounding effects of active tobacco smoking and other methodological limitations. Future large-scale studies are warranted to confirm our findings.

Mutagen sensitivity and environmental exposures as contributing causes of chromosome 3p losses in head and neck cancers.

The interaction between environmental exposures and host susceptibility may lead to specific mutational events within head and neck squamous cell carcinoma (HNSCC). Furthermore, this interplay may determine not only the probability of cancer development but also the biologic characteristics of the tumor once it occurs. To better understand the relationship of mutagen sensitivity and tobacco and/or alcohol consumption on HNSCC carcinogenesis, we examined loss of heterozygosity on chromosome 3p in 58 HNSCCs using 10 microsatellite markers. Mutagen sensitivity was determined in vitro by quantitating bleomycin-induced chromatid breaks utilizing peripheral blood lympocytes from respective patients. Forty-six of the 58 invasive cancers showed allelic loss at one or more loci. Consistent with previous investigations, three discrete regions of deletions were identified: 3p13-14.2, 3p21.1-21. 2, and 3p25.1-26.1. The frequency and types of deletions were dependent upon tobacco and alcohol exposures. The distal region of 3p but not the remaining two regions was most frequently influenced by tobacco exposure. In contrast, heavy alcohol use when combined with tobacco use was associated with whole-arm loss of 3p rather than identifiable site-specific damage. Furthermore, this combined influence of alcohol and tobacco exposures on whole-arm loss was most apparent in those patients who expressed mutagen-sensitivity; the odds ratio of whole-arm loss increasing from 2.67 (95% CI 0. 21-33.49) in those individuals who were mutagen resistant to 13.5 (95% CI 1.3-136.0; P = 0.02 by Fisher's exact test) in those who were mutagen sensitive. An assessment of clinical parameters in this population demonstrated that patients with whole-arm loss were more likely to present with cervical lymph node metastases and advanced stage disease than patients with partial losses. Results indicate that various environmental exposures as well as the expression of mutagen sensitivity will influence the types of chromosome 3p allelic losses in head and neck cancers as well as the behavior of disease once it develops.

Improving degenerate oligonucleotide primed PCR-comparative genomic hybridization for analysis of DNA copy number changes in tumors.

Combining degenerate oligonucleotide-primed PCR (DOP-PCR) with comparative genomic hybridization (CGH) has made it possible to analyze genomic changes in single cells. Although DOP-PCR-CGH methodology has been reported, the reproducibility of the method has been uncertain. We have developed a reproducible DOP-PCR-CGH protocol by systematically evaluating different labeling methods (including nick translation, PCR incorporation, and random-primed labeling) and different hybridization mixtures (including amplified test DNA vs. amplified reference DNA, termed homo-hybridization; and amplified test DNA vs. unamplified reference DNA or vice versa, termed hetero-hybridization). We have analyzed DNA samples obtained from 16 tissue sources including fresh/frozen normal and tumor samples, formalin fixed and paraffin embedded tumor tissue, and tumor cell lines by using differently labeled probes and hybridization combinations, and we calculated the corresponding rate (CR) of DOP-PCR-CGH with standard CGH. We found that homo-hybridization produced reproducible results with high CRs as compared to standard CGH (91-100% CR, mean 97%); In contrast, hetero-hybridization failed to generate reproducible hybridization with low CRs (57-97% CR, mean 80%; chi(2) = 1245.8, P<0.0001), high background, uneven hybridization, and false deletions or amplifications. In addition, our improved DOP-PCR protocol raised the amplification efficiency at least five times as compared to previously reported protocols, allowing for the detection of genomic imbalances in as little as 12.5 pg of starting DNA. In conclusion, the DOP-PCR-CHG homo-hybridization method, especially when combined with labeling by nick translation, is reliable and reproducible. The method can be used in screening for genomic imbalances using minute amounts of tumor DNA, thereby facilitating CGH application. Genes Chromosomes Cancer 28:395-403, 2000.

Comparison of GSTM polymorphisms and risk for oral cancer between African-Americans and Caucasians.

Two members of the mu class of glutathione S-transferase (GST) genes, GSTM1 and GSTM3, have polymorphic alleles which have been associated with altered levels of GST mu protein expression and may be linked to increased risk for several tobacco-related cancers. Oral cancer is a tobacco-related disease that affects African-American men at a significantly higher incidence than Caucasian men. To examine the potential role of GSTM polymorphisms in risk for oral cancer in African-Americans and Caucasians, the prevalences of the GSTM1 null and GSTM3 intron 6 polymorphisms were examined in 63 African-American and 101 Caucasian patients with histologically confirmed primary oral cancer, as well as in 133 African-American and 213 Caucasian matched control subjects. In African-Americans, the odds ratio for oral cancer associated with the GSTM1 (0/0) genotype was 3.1 [95% confidence interval (CI) = 1.1-8.5], with the association between the GSTM1 (0/0) genotype and oral cancer risk strongest in heavy smokers [i.e. > 24 pack-years; odds ratio (OR) = 5.4, 95% CI = 1.2-24]. Using the potentially most protective GSTM1 [+]/GSTM3 (B/B) genotype as the reference group, increased risk for oral cancer was observed in African-Americans with the GSTM1 [+]/GSTM3 [(A/A) + (A/B)] (OR = 2.2, 95% CI = 0.82-6.0), GSTM1 (0/0)/GSTM3 (B/B) (OR = 4.3, 95% CI = 1.1-16), and GSTM1 (0/0)/GSTM3 [(A/A) + (A/B)] (OR = 6.6, 95% CI = 1.2-38) genotypes (P < 0.01, trend test). No significant associations were observed between GSTM genotype and oral cancer risk in Caucasians. These results suggest that the GSTM1 null and GSTM3 intron 6 polymorphisms play an important role in risk for oral cancer among African-Americans and implicates the mu class of GSTs as important tobacco carcinogen detoxifying enzymes in this population.

A survey of smoking status and cancer risk perceptions among participants attending a hospital-based head and neck screening program.

Abstract Screening for head and neck cancer is underutilized. Given that lack of knowledge of the risk factors may partially account for screening underutilization. we surveyed subjective risk and knowledge of risk factors for head and neck cancer among 124 individuals who attended a free. hospital-based head and neck cancer screening. Few participants were current smokers. Most attendees perceived their risk as similar to others of their age and sex. Personal health habits comprised almost all of the risk-decreasing factors, yet less than half of the risk-increasing factors. generated. Personal habits were less frequently endorsed than factors such as pollution and heredity. Those who mentioned a risk behavior, or a family cancer history, reported higher subjective risk. Those who mentioned a personal health habit reported lower subjective risk. Results highlight needed efforts to increase screening among high-risk individuals through targeted education messages.

Marijuana use and increased risk of squamous cell carcinoma of the head and neck.

Marijuana is the most commonly used illegal drug in the United States. In some subcultures, it is widely perceived to be harmless. Although the carcinogenic properties of marijuana smoke are similar to those of tobacco, no epidemiological studies of the relationship between marijuana use and head and neck cancer have been published. The relationship between marijuana use and head and neck cancer was investigated by a case-control study of 173 previously untreated cases with pathologically confirmed diagnoses of squamous cell carcinoma of the head and neck and 176 cancer-free controls at Memorial Sloan-Kettering Cancer Center between 1992 and 1994. Epidemiological data were collected by using a structured questionnaire, which included history of tobacco smoking, alcohol use, and marijuana use. The associations between marijuana use and head and neck cancer were analyzed by Mantel-Haenszel methods and logistic regression models. Controlling for age, sex, race, education, alcohol consumption, pack-years of cigarette smoking, and passive smoking, the risk of squamous cell carcinoma of the head and neck was increased with marijuana use [odds ratio (OR) comparing ever with never users, 2.6; 95% confidence interval (CI), 1.1-6.6]. Dose-response relationships were observed for frequency of marijuana use/day (P for trend <0.05) and years of marijuana use (P for trend <0.05). These associations were stronger for subjects who were 55 years of age and younger (OR, 3.1; 95% CI, 1.0-9.7). Possible interaction effects of marijuana use were observed with cigarette smoking, mutagen sensitivity, and to a lesser extent, alcohol use. Our results suggest that marijuana use may increase the risk of head and neck cancer with a strong dose-response pattern. Our analysis indicated that marijuana use may interact with mutagen sensitivity and other risk factors to increase the risk of head and neck cancer. The results need to be interpreted with some caution in drawing causal inferences because of certain methodological limitations, especially with regard to interactions.

Subsurface tumor progression investigated by noninvasive optical second harmonic tomography.

Nonlinear optical imaging with femtosecond (10(-15)-second) laser technology was used to evaluate the subsurface tumor progression in control, dysplasia, and cancerous 7, 12-dimethylbenz[a]anthracene-treated hamster cheek pouch mucosa tissues. Two-dimensional images of hamster cheek pouch mucosa tissues were obtained by scanning the second harmonic signal at various sagittal and axial positions. The spatial mapping of the second harmonic signals showed depth differentiation between normal, dysplasia, and a more advanced cancerous state. This nonlinear optical method offers a noninvasive in situ imaging tool to the medical community.

Family history of cancer, mutagen sensitivity, and increased risk of head and neck cancer.

To evaluate individual cancer susceptibility, 170 previously untreated patients with pathologically-confirmed squamous cell carcinoma of the oral cavity, pharynx, and larynx, and 175 age- and sex-matched health controls were investigated for the occurrence of cancer in first-degree relatives along with other established risk factors for head and neck cancer. More than 54% of these subjects were assayed for mutagen sensitivity by quantifying in-vitro bleomycin-induced chromosomal breaks within peripheral blood lymphocytes. After adjusting for age, gender, education, family income, tobacco and alcohol consumption, the odds ratio associated with three or more first-degree relatives with cancer at any site was 3.79 (95% CI 0.9-15.9) with a linearly-increased trend in risk (P = 0.040). Significantly elevated risk was found to be associated with a history of cancer within siblings (OR = 2.61, 1.2-5.6, P = 0.014). Patients with a family cancer history and mutagen sensitivity were at greatest risk (OR = 7.88, 2.5-25.3, P = 0.005), indicating an additive interactive effect. The findings suggested that genetic familial influence is important in the causation of head and neck cancer.

Association between glutathione S-transferase pi genetic polymorphisms and oral cancer risk.

Polymorphisms in the gene encoding the glutathione S-transferase (GST) pi metabolizing enzyme have previously been associated with susceptibility to various cancers. In this study, the importance of GSTP1 genotypes as determinants of risk for oral cancer was assessed by examining the prevalence of GSTP1 alleles in 157 incident oral cancer cases and 260 non-cancer control individuals frequency-matched by race, sex, and age at diagnosis (+/- 5 years). The GSTP1*A, GSTP1*B, GSTP1*C, and GSTP1*D alleles were elucidated by polymerase chain reaction-restriction fragment length polymorphism analysis of polymorphisms present in codons 105 (isoleucine:valine) and 114 (alanine:valine) of the GSTP1 gene. Increased risk for oral cancer was observed in individuals who were homozygous for any combination of GSTP1 polymorphic alleles (i.e. *B, *C, and/or *D alleles; odds ratio = 2.4, 95% confidence interval = 1.2-4.8). Similar risk was observed in both Caucasians (odds ratio = 2.6, 95% confidence interval = 1.1-6.2) and African-Americans (odds ratio = 2.3, 95% CI = 0.68-7.5). A greater risk was observed in individuals with the GSTP1 (Var/Var) genotype who were exposed to low levels of smoking (i.e. < or = 20 pack-years [py], odds ratio = 3.4, 95% confidence interval = 1.1-11) than among heavier smokers (i.e. > 20 pack-years [py], odds ratio = 1.4, 95% confidence interval = 0.48-4.0). These results suggest that GSTP1 genotype may play a role in risk for oral cancer particularly among lighter smokers.

A prospective phase II trial of concomitant chemotherapy and radiotherapy with delayed accelerated fractionation in unresectable tumors of the head and neck.

BACKGROUND: Our study is a prospective evaluation of unresectable malignant cancers of the head and neck treated with concomitant chemotherapy and radiotherapy (RT) using delayed accelerated fractionation (concomitant boost). METHODS: Between January 1988 and March 1995, 82 patients with unresectable cancers of the head and neck were enrolled in this phase II study. Of these, 52 patients were treated and followed for a minimum of 3 years and are the subject of this analysis. All patients had T4 lesions and were stage IV according to the American Joint Committee on Staging Criteria (AJCC). Patients received RT with accelerated fractionation to a total of 70 Gy in 6 weeks using a concomitant-boost technique. Concomitant cis platin (100 mg/M2) was given on days 1 and 22 of RT. Twenty-seven patients received mitomycin-C (7.5 mg/M2) on days 1 and 22, and 1 patient received mitomycin-C on day 1. In addition, 27 patients received adjuvant chemotherapy with cis platin and vinblastine. The mean follow-up was 45 months (range, 36-72 months). The minimum follow-up for surviving patients in 3 years. RESULTS: At 3 years, the local control rate was 58%. Three-year local control rates for paranasal sinus, nasopharynx, oropharynx, and larynx/hypopharynx were 78%, 78%, 64%, and 100%, respectively. For all patients, the distant-metastasis-free survival was 56%, and the overall survival rate was 36%. Patients with oral cavity cancers experienced worse overall survival versus other sites, 0% versus 47% (p = .03). Salivary cancers also showed worse survival versus other sites, 0% versus 47%, but was not statistically significant. Severe acute complications occurred in 34% of patients. Treatment-related toxicity also resulted in the death of 2 patients. Severe late complications occurred in 7% of patients. CONCLUSIONS: Treatment of this poor prognostic group of patients with aggressive chemotherapy and RT produced surprisingly good local control and survival.

Green tea regulates cell cycle progression in oral leukoplakia.

BACKGROUND: A complete in vitro multi-stage carcinogenesis model for oral cancer was developed to examine chemopreventive strategies. In the present study, the effects of EGCG [(-)-epigallocatechin-3-gallate], the major constituent of green tea, is being examined to understand mechanisms of action. METHODS: Effects of EGCG on the cell populations were examined with growth assays, cell cycle analysis, and western blots for retinoblastoma protein (pRB). RESULTS: In each cell type, EGCG inhibited growth, with a decrease in efficacy as cells progressed from normal to cancer. A G1 block was induced with an increase in the underphosphorylated form of pRB; EGCG-induced inhibition was not permanent, cells recovered, and no resistance developed. CONCLUSIONS: Our multistage carcinogenesis model for chemoprevention was effective in defining the chemopreventive value of EGCG. The observation that cancerous oral epithelium was less responsive than normal or dysplastic tissues has implication in the use of this agent, and the mechanisms responsible for this result remain to be defined.

Squamous cell carcinoma of the tongue in young patients: a matched-pair analysis.

BACKGROUND: Tongue cancer is seen with increasing frequency in young individuals. There is controversy concerning the clinical course and outcome for oral tongue cancer in young patients. METHODS: A retrospective review of 36 patients under 40 years of age with squamous cell carcinoma of the tongue was performed. These patients were matched to an older population. The 5-year disease-free survival; rates of local, regional, and distant failure; and rate of second primary tumor were determined for both populations. RESULTS: The 5-year disease-free survival for the young patients was 62% versus 69% in the older population (p = .30). Ten of 36 (28%) of younger patients recurred locally versus five of 36 (14%) of the older patients (p = .11). Nine of 36 (25%) younger patients recurred regionally in the younger group versus six of 36 (17%) patients in the older group (p = .25). Sixteen of 36 (44%) of the younger patients had locoregional failure versus eight of 36 (22%) of the older patients (p < .05). The rates of metastatic disease and second primary lesions were similar in both populations. CONCLUSIONS: In this series, younger patients with squamous cell carcinoma of the oral tongue had a higher rate of locoregional recurrence rate than did older patients. This did not translate into a survival difference.

In vivo native cellular fluorescence and histological characteristics of head and neck cancer.

Native cellular fluorescence (NCF) represents the innate capacity of tissues to absorb and emit light of a specified wavelength. The ability to define the relationship of in vivo NCF with biological characteristics of neoplastic disease may allow for an improved understanding of the clinical course of disease. Head and neck cancers from 35 patients were evaluated in vivo for NCF characteristics using a xenon lamp-based spectrometer coupled to a handheld fiberoptic probe. Spectral assessment was limited to lambda 450-nm emission characteristics, in which tissues were excited at various wavelengths, ranging from lambda 290 nm to lambda 415 nm, and the intensity of lambda 450 nm emission was recorded. Each cancer was subsequently biopsied and assessed for histological differentiation by a pathologist who was blinded to NCF analysis. Considerable variation in spectral characteristics between head and neck cancers was identified, which was determined, in part, by NCF characteristics of the normal mucosa from the same patient. Poorly differentiated tumors were more likely than well- or moderately differentiated tumors to have lower excitation maxima (P < 0.05 by ANOVA). Most significantly, the tumor differentiation status, as well as the probability of demonstrating recurrent disease, could also be related to the NCF characteristics of the patient's normal mucosa from the same site within the upper aerodigestive tract. NCF analysis may represent an effective tool to identify biological characteristics of head and neck tumors in vivo without the need for invasive biopsies. Results suggest the need to explore the determinants of NCF characteristics expressed by clinically normal mucosa.

Blood and urine levels of tea catechins after ingestion of different amounts of green tea by human volunteers.

The inhibitory activity of tea against tumorigenesis has been demonstrated in many animal models and has been suggested by some epidemiological studies. Such activity has generally been attributed to tea catechins. To understand the bioavailability of tea catechins in humans, we gave 18 individuals different amounts of green tea and measured the time-dependent plasma concentrations and urinary excretion of tea catechins. After taking 1.5, 3.0, and 4.5 g of decaffeinated green tea solids (dissolved in 500 ml of water), the maximum plasma concentration (Cmax) of (-)-epigallocatechin-3-gallate (EGCG) was 326 ng/ml, the Cmax of (-)-epigallocatechin (EGC) was 550 ng/ml, and the Cmax of (-)-epicatechin (EC) was 190 ng/ml. These Cmax values were observed at 1.4-2.4 h after ingestion of the tea preparation. When the dosage was increased from 1.5 to 3.0 g, the Cmax values increased 2.7-3.4-fold, but increasing the dose to 4.5 g did not increase the Cmax values significantly, which suggested a saturation phenomenon. The half-life of EGCG (5.0-5.5 h) seemed to be higher than the half-life of EGC or EC (2.5-3.4 h). EGC and EC, but not EGCG, were excreted in the urine. Over 90% of the total urinary EGC and EC was excreted within 8 h. When the tea dosage was increased, the amount of EGC and EC excretion seemed to increase, but a clear dose-response relationship was not observed. The present study provides basic pharmacokinetic parameters of green tea catechins in humans; these parameters may be used to estimate the levels of these compounds after drinking tea.