Plasma zinc and vitamin A in human squamous carcinoma of the esophagus

Zinc treatment reverses and anti-Zn-regulated miRs suppress esophageal carcinomas in vivo

Esophageal squamous cell carcinoma (ESCC) is a deadly disease with few prevention or treatment options. ESCC development in humans and rodents is associated with Zn deficiency (ZD), inflammation, and overexpression of oncogenic microRNAs: miR-31 and miR-21. In a ZD-promoted ESCC rat model with upregulation of these miRs, systemic antimiR-31 suppresses the miR-31-EGLN3/STK40-NF-κB-controlled inflammatory pathway and ESCC. In this model, systemic delivery of Zn-regulated antimiR-31, followed by antimiR-21, restored expression of tumor-suppressor proteins targeted by these specific miRs: STK40/EGLN3 (miR-31), PDCD4 (miR-21), suppressing inflammation, promoting apoptosis, and inhibiting ESCC development. Moreover, ESCC-bearing Zn-deficient (ZD) rats receiving Zn medication showed a 47% decrease in ESCC incidence vs. Zn-untreated controls. Zn treatment eliminated ESCCs by affecting a spectrum of biological processes that included downregulation of expression of the two miRs and miR-31-controlled inflammatory pathway, stimulation of miR-21-PDCD4 axis apoptosis, and reversal of the ESCC metabolome: with decrease in putrescine, increase in glucose, accompanied by downregulation of metabolite enzymes ODC and HK2. Thus, Zn treatment or miR-31/21 silencing are effective therapeutic strategies for ESCC in this rodent model and should be examined in the human counterpart exhibiting the same biological processes.

Nutritional Support in Patients with Cancer of the Esophagus: Impact on Nutritional Status, Patient Compliance to Therapy, and Survival

AIMS AND BACKGROUND

The multimodal approach to patients with esophageal squamous cell carcinoma often includes polychemotherapy combined with radiation therapy. Cancer dysphagia and drug-related anorexia, mucositis and vomiting can all lead to malnutrition. The aim of this study was to analyze the impact of the administration of enteral nutrition (EN) on the patient's nutritional status, tolerance of chemotherapy and radiotherapy, and final oncological outcome.

METHODS

Fifty esophageal cancer patients who were to be submitted to chemotherapy (days 1-4 5-fluorouracil (FU) 1 g/m2/day and cisplatin (CDDP) 100 mg/m2/day 1) for two cycles plus radiotherapy (31 Gy) were referred to the Nutrition Support Unit prior to any therapy due to their malnourished status. Twenty-nine dysphagic patients received nutrition via tube (37 kcal/kg/day + 2.0 g proteins/kg/day for 34 days), while 21 others who were not dysphagic were given a standard oral diet (SD). The patients who received EN had a more severe weight loss than the SD patients (16.8% vs 12.8%, P <0.02).

RESULTS

The dose of administered EN represented 86% of the planned support, and 70% of the nutritional therapy was administered in the home setting. Administration of EN support resulted in stable body weight and unchanged levels of visceral proteins, while SD patients had a decrease in body weight, total proteins and serum albumin (P <0.01). There was no difference between the two groups in terms of tolerance and response to cancer therapy, suitability for radical resection and median survival (9.5 months).

CONCLUSIONS

EN in patients with cancer of the esophagus undergoing chemotherapy and radiotherapy is well tolerated, feasible even in the home setting, prevents further nutritional deterioration and achieves the same oncological results in dysphagic patients as those achieved in non-dysphagic patients.

Serum and tissue zinc in epithelial malignancies: a meta-analysis

BACKGROUND AND OBJECTIVES

Current studies give us inconsistent results regarding the association of neoplasms and zinc(II) serum and tissues concentrations. The results of to-date studies using meta-analysis are summarized in this paper.

METHODS

Web of Science (Science citation index expanded), PubMed (Medline), Embase and CENTRAL were searched. Articles were reviewed by two evaluators; quality was assessed by Newcastle-Ottawa scale; meta-analysis was performed including meta-regression and publication bias analysis.

RESULTS

Analysis was performed on 114 case control, cohort and cross-sectional studies of 22737 participants. Decreased serum zinc level was found in patients with lung (effect size = -1.04), head and neck (effect size = -1.43), breast (effect size = -0.93), liver (effect size = -2.29), stomach (effect size = -1.59), and prostate (effect size = -1.36) cancers; elevation was not proven in any tumor. More specific zinc patterns are evident at tissue level, showing increase in breast cancer tissue (effect size = 1.80) and decrease in prostatic (effect size = -3.90), liver (effect size = -8.26), lung (effect size = -3.12), and thyroid cancer (effect size = -2.84). The rest of the included tumors brought ambiguous results, both in serum and tissue zinc levels across the studies. The association between zinc level and stage or grade of tumor has not been revealed by meta-regression.

CONCLUSION

This study provides evidence on cancer-specific tissue zinc level alteration. Although serum zinc decrease was associated with most tumors mentioned herein, further--prospective--studies are needed.

Cellular mechanisms of zinc dysregulation: a perspective on zinc homeostasis as an etiological factor in the development and progression of breast cancer

Worldwide, breast cancer is the most commonly diagnosed cancer among women and is the leading cause of female cancer deaths. Zinc (Zn) functions as an antioxidant and plays a role in maintaining genomic stability. Zn deficiency results in oxidative DNA damage and increased cancer risk. Studies suggest an inverse association between dietary and plasma Zn levels and the risk for developing breast cancer. In contrast, breast tumor biopsies display significantly higher Zn levels compared with normal tissue. Zn accumulation in tumor tissue also correlates with increased levels of Zn importing proteins. Further, aberrant expression of Zn transporters in tumors correlates with malignancy, suggesting that altered metal homeostasis in the breast could contribute to malignant transformation and the severity of cancer. However, studies have yet to link dysregulated Zn transport and abnormal Zn-dependent functions in breast cancer development. Herein, we summarize studies that address the multi-modal role of Zn dyshomeostasis in breast cancer with respect to the role of Zn in modulating oxidative stress, DNA damage response/repair pathways and cell proliferation/apoptosis, and the relationship to aberrant regulation of Zn transporters. We also compare Zn dysregulation in breast tissue to that of prostate, pancreatic and ovarian cancer where possible.

The levels of zinc and molybdenum in hair and food grain in areas of high and low incidence of esophageal cancer: a comparative study

The outcome of different studies on the role of Zn & Mo in esophageal cancer (EC) is conflicting. Here, the levels of those elements in hair as well as food grain of two different ethnic populations across two continents have been studied to explore their role in EC. Two different ethnic populations are taken from (i) Eastern Cape, South Africa (RSA), an area of very high incidence of EC and (ii) West Bengal, India, an area of low incidence of that disease. Each ethnic population is divided into two groups: case and control (n=30 for all groups). Hair samples from all groups and food grains from RSA and India are analyzed for Zn & Mo content. This study shows a strong correlation between reduced levels of those elements in hair and the development of EC in RSA (both Zn & Mo: p<0.0001), though it is only suggestive in Indian context (both Zn & Mo: p≥0.05). Interestingly, control group of RSA shows significantly reduced level of those elements in hair even with respect to Indian case group (Zn: p<0.001 & Mo: p<0.00001). Food grain from RSA has significantly reduced level of those elements with respect to India (both Zn & Mo: p<0.0001). This deficiency of Zn & Mo in food grains can be correlated to the deficiency of those elements in hair of RSA population. The deficiency of Zn & Mo can be correlated to the development of EC.

Structural features of the NAD-dependent in situ retinoic acid supply system in esophageal mucosa

BACKGROUND

We previously reported that an NAD-dependent in situ retinoic acid supply system, which comprises some isoforms of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) and provides retinoic acid from retinol via a 2-step oxidation process, exists in the rat esophagus. Herein, their isoforms responsible for the pathway and its localization in the rat esophagus was examined.

METHODS

The expressions of mRNAs of various isoforms of ADH and ALDH were examined in the fraction mainly comprising mucosal layer of the rat esophagus by RT-PCR. Expression levels of Class IV ADH and ALDH 1A1 were compared between the fractions and that mainly comprising muscle layer of the rat esophagus by quantitative PCR. The catalytic activities producing retinoic acid from retinal were compared between the 2 fractions and its optimum pH was also determined.

RESULTS

Classes I, III, and IV ADHs and ALDHs 1A1 and 3A1 were predominant isoforms in the rat esophageal mucosa. The expression levels of mRNA of Class IV ADH and ALDH 3A1 were significantly higher in the mucosal than in the muscle layer. Consistently, the catalytic activities producing retinoic acid from retinal were significantly higher in the former than the latter. The optimum pH of the process was 9.0.

CONCLUSIONS

Considering the affinities for retinol and retinal of ADHs and ALDHs expressed in the rat esophagus, the NAD-dependent in situ retinoic acid supply system in the rat esophagus is thought to comprise Class IV ADH and ALDH 1A1. In the rat esophagus, the system exists predominantly in the mucosal layer.

Association between copper excess, zinc deficiency, and TP53 mutations in esophageal squamous cell carcinoma from Kashmir Valley, India--a high risk area

Trace element deficiency or excess is implicated in the development or progression in some cancers. Here we report the elevated level of copper and low level of zinc in the plasma of esophageal cancer patients in Kashmir India--a high incidence area. The average level of copper was significantly higher (P < 0.0001) for patients than for controls, with a mean concentration of 169 microg/dl and 149 microg/dl for patients and controls, respectively. The control group consisted of 55 healthy individuals matched for age, sex, and place of residence of the patients. In contrast, the average level of zinc in patients was significantly lower than in controls (P < 0.0001), with a mean concentration of 86.8 microg/dl and 96.1 microg/dl for patients and controls, respectively. The levels of both copper and zinc showed significant differences based on gender and age in patients as compared to controls. Similarly, smokers depicted a significant increase in serum copper (N = 39, P = 0.002) and a decrease in serum zinc approaching level of significance in the patient group as compared to controls. The copper and zinc levels were significantly altered in patients (N = 40) when compared to controls as a function of snuff consumption. The differences in the levels of copper and zinc showed significant association with the consumption of local salted tea up to 1,500 ml per day, but the changes were insignificant beyond that. Patients with poorly differentiated tumors (N = 7) had a higher copper concentration than those with moderately or well-differentiated tumors (P < 0.0001). To validate the general notion that imbalance in copper and zinc levels may lead to higher prevalence of TP53 mutations, we compared the 3 variables, and no association was found between copper concentration and TP53 mutation status; but patients with TP53 mutant tumor had lower zinc levels than those with no mutation. In conclusion, our results point toward a role of the trace element imbalance in the esophageal tumorigenesis in high-risk Kashmiri population exposed to a range of nitroso compounds or their precursors. Further prospective cohort studies are warranted to determine whether change in the plasma zinc and copper homeostasis may represent an independent risk factor for this malignancy as well as a possible target for preventive intervention.

Toenail zinc level and gastric cancer risk in Cali, Colombia

PURPOSE

To examine the associations between gastric cancer (GC) risk and the zinc levels in toenail clippings, we conducted a hospital-based case-control study during the period from 2000 to 2002 in Cali, Colombia.

METHODS

Toenail clippings and information on lifestyles including dietary habits were obtained from 156 GC patients newly diagnosed in three hospitals in Cali and 287 controls selected from non-cancer patients who were hospitalized in the same hospitals as GC patients. Zinc concentrations in toenail clippings were examined using inductively coupled plasma mass spectrometry.

RESULTS

An inverse association was observed between toenail zinc level and GC risk (P for trend = 0.039). When we examined this association separately for current and former smokers and non-smokers, only current-smokers showed a significant inverse association (P for trend = 0.035). Histology specific analysis revealed that this inverse association was stronger when we limited GC cases with intestinal-type and their matched controls (P for trend < 0.001). This association was also observed in the carcinomas located in the upper two-thirds of the stomach (P for trend = 0.004) but not in carcinomas in the lower-third of the stomach (P for trend = 0.727).

CONCLUSIONS

There was an inverse association between toenail zinc level and GC risk. However, the association was limited to smokers, intestinal-type GC, and tumors in the upper two-thirds of the stomach. Further studies seem warranted to confirm our findings.

Meat as a component of a healthy diet - are there any risks or benefits if meat is avoided in the diet?

Meat is frequently associated with a "negative" health image due to its "high" fat content and in the case of red meat is seen as a cancer-promoting food. Therefore, a low meat intake, especially red meat is recommended to avoid the risk of cancer, obesity and metabolic syndrome. However, this discussion overlooks the fact, that meat is an important source for some of micronutrients such as iron, selenium, vitamins A, B12 and folic acid. These micronutrients are either not present in plant derived food or have poor bioavailability. In addition, meat as a protein rich and carbohydrate "low" product contributes to a low glycemic index which is assumed to be "beneficial" with respect to overweight, the development of diabetes and cancer (insulin resistance hypothesis). Taken together meat is an important nutrient for human health and development. As an essential part of a mixed diet, meat ensures adequate delivery of essential micronutrients and amino acids and is involved in regulatory processes of energy metabolism.

Inverse expression of dihydrodiol dehydrogenase and glutathione-S-transferase in patients with esophageal squamous cell carcinoma

We investigated the significances of the expressions of dihydrodiol dehydrogenase (DDH) and glutathione-S-transferase (GST) in patients with esophageal squamous cell carcinoma (ESCC). By using immunohistochemistry, we measured expressions of DDH, GST, COX-2, nm23-H1, HER-2/neu and mdr-1 in 145 patients with ESCC. Expression of DDH was confirmed by immunoblotting and reverse transcription-polymerase chain reaction. Relation between DDH expression and clinicopathological parameters was analyzed by statistical analysis. Difference of survivals between different groups was compared by a log rank test. DDH overexpression was detected in 66.9% of pathological sections (97/145) and in 41.6% of metastatic lymph nodes (37/89). The nucleotide sequencing of DNA fragments from 16 tumorous specimens showed that the major isoform was DDH2 for ESCC. GST expression, however, was only detected weakly in 24 patients (16.6%). For patients with ESCC, DDH overexpression was positively correlated with smoking habit, tumor stage, number of metastatic lymph nodes, lymphovascular invasion and COX-2 expression, and inversely correlated with GST and nm23-H1 expressions, but not related to mdr-1 or HER-2/neu expressions. As compared to DDH overexpressed group, patients with low DDH expression had significantly lower incidence of tumor recurrences and better survival (p = 0.026). Using univariate analysis, prognostic factors included tumor stage, number of metastatic lymph nodes, cell differentiation, lymphovascular invasion and expressions of DDH and nm23-H1. Multivariate analysis showed significant correlation of tumor stage, number of metastatic lymph nodes and nm23-H1 expression with patient's survival. In conclusion, inverse expressions of DDH and GST may be associated with carcinogenesis and disease progression for ESCC patients, but their biological function and pathophysiological regulation in tumors require additional studies.

Extracellular zinc stimulates ERK-dependent activation of p21(Cip/WAF1) and inhibits proliferation of colorectal cancer cells

Zinc is an important trace element in the body and is involved in both the proliferation and growth arrest of many kinds of cells including colorectal epithelial cells. The aim of this study was to identify the molecular mechanism of the growth regulation of colorectal cancer cells by extracellular zinc. Zinc-stimulated activation of the mitogen-activated protein kinase (MAPK) cascade was measured by immunoblotting and Elk-1 dependent trans-reporter gene expression, and zinc-stimulated p21(Cip/WAF1) activation by immunoblotting, Northern blot analysis and immunochemistry. Cell proliferation was measured by thymidine and bromodeoxyuridine (BrdU) incorporation. By treating colorectal cancer cells with 100 microM ZnCl2, MAPKs were activated in two different phases, the initial weak activation occurred within 5 min and this was followed by a stronger and more prolonged activation. Zinc concomitantly activated Raf-1-MEK-MAPK kinases, and induced Elk-1 dependent trans-reporter gene expression. Prolonged activation of MAPKs by 100 microM of ZnCl2 resulted in the induction and nuclear localization of p21(Cip/WAF1) and was related to the inhibition of both thymidine and BrdU incorporations. These results not only suggest the presence of a mechanism for p21(Cip/WAF1) dependent negative regulation of colorectal cancer cell growth by zinc but also suggest potential usage of zinc to control the growth of colorectal cancer cells.

Detection of Epstein-Barr virus in esophageal squamous cell carcinoma in Taiwan

OBJECTIVE

Recently, an association between viral infection and the development of esophageal carcinoma has been reported, particularly the human papilloma virus (HPV) and Esptein-Bar virus (EBV). However, geographic variation in carcinogenesis is realized. In this study, we investigate the viral carcinogenesis and the biologic effect of viral infection on esophageal squamous cell carcinoma (ESCC) in Taiwan.

METHODS

To determine the association of viral infection (EBV and HPV) with ESCC, we applied polymerase chain reaction (PCR), immunohistochemistry, and in situ hybridization (ISH) to examine 119 surgical specimens from different sites of esophagus in 31 ESCC patients. Additionally, an immunoperoxidase method was used to detect EBV latent membrane protein-1 (LMP-1), p53, CD45RO (UCHL-1), Fas ligand (Fas L), and RNA ISH with oligonucleotide sequences was used to detected interleukin-6 (IL-6) mRNA.

RESULTS

By PCR, EBV DNA was detected in 11 cases (35.5%). Expression of EBERs in ESCC was further confirmed with ISH. Nonetheless, no LMP-1 expression was detected. On the other hand, human papillomavirus (HPV) was identified in only one case (3.2%) of ESCC. Furthermore, HPV was located by ISH in the distant normal region rather than in tumor cells. In EBV-positive cases, accumulation of p53 protein was detected in 10 lesions (91%); CD45RO+ lymphocytes together with expressions of FasL and IL-6 were respectively identified in 100%, 63.6%, and 54.5% of 11 EBV-positive lesions. Interestingly, in the EBV-negative cases (n = 20), p53 protein was detected in 40% of lesions; CD45RO 30%; FasL 50%, and IL-6 10%.

CONCLUSIONS

In this study, no correlation was found between the presence of EBV in ESCC and the patients' age, sex, as well as survival. Although our results indicate that EBV could be associated with ESCC, the clinical role of EBV in ESCC remains to be determined.

Zinc deficiency in head and neck cancer patients

BACKGROUND

Although a great deal of attention has been given to protein and calorie malnutrition in patients with head and neck cancer, zinc status has not been assessed properly in such patients in the past.

METHODS

In this study we characterized zinc status by cellular zinc criteria and assessed several measures of protein and calorie malnutrition in patients with head and neck cancer. We determined prognostic nutritional index (PNI) based on serum albumin, serum transferrin, triceps skin fold measures, and delayed hypersensitivity, as proposed by Buzby et al. In this study, the baseline zinc status and PNI of 60 head and neck cancer patients were correlated with the tumor size and overall stage of the disease.

RESULTS

Our results showed that the tumor size and overall stage correlated significantly to zinc status whereas no correlation was seen with PNI, alcohol intake, or smoking in our study subjects.

CONCLUSION

We conclude that zinc status is a better indicator of tumor burden and stage of the disease in head and neck cancer patients than the patients' overall nutritional status.

Concentrations of some major and minor elements in larynx tissues with and without cancer

In this study, concentrations of some major and minor elements were determined in the larynx tissues with and without cancer, and results obtained were statistically compared. No meaningful differences were found between sodium, potassium, calcium and copper concentrations in cancer tissues, corresponding cancer-free adjacent tissues and in control larynx tissues. Phosphate concentrations of the cancer tissues were higher compared with cancer-free adjacent tissues and control tissues. Iron, zinc and magnesium concentrations were found increased in both cancer and corresponding cancer-free adjacent tissues relative to control values. Intra- and inter-element correlations established within and between groups indicated that relations between elements were also disordered in the cancer tissues. We suggest that the changed element status of cancerous larynx tissues may arise from increased requirements of cancer tissues for some elements such as iron, zinc, magnesium and phosphate.

Water contamination and esophageal cancer at Gassim Region, Saudi Arabia

Between January 1980 and December 1982, 183 patients with histologically confirmed carcinoma of the esophagus who were referred to a tertiary referral hospital were studied. Thirty-two (17%) patients were referred from Gassim Region at the north central part of Saudi Arabia. In contrast, only 5% of total cancer patient referrals were from this area. A case-control study showed a significant regional difference within Saudi Arabia and the most referrals from Gassim area. A prospective case-control study showed persistently high numbers of referrals from that region during 1983-1987. When patients from Gassim Region were compared with those referred from other locations, no statistical differences were noted between the two groups except for the source of drinking water. Water analysis from Gassim area showed a high solid content with elevated levels of calcium, magnesium, and to a lesser extent, chromium iron, cadmium, and cobalt. Traces of petroleum oil were found in five of six water samples from Gassim during 1983, compared with 3 of 49 samples from other areas. Mutagenicity tests on water specimens form Gassim Region indicated the presence of possible carcinogens. It is being suggested that the high prevalence of esophageal cancer in this region may be related to contamination of water by impurities such as petroleum oils. Malnutrition, particularly vitamin A deficiency, as well as other factors may have promoted such malignancies.

Concentration of zinc and zinc-copper superoxide dismutase activity in red blood cells in normals and children with cancer

Zinc concentrations and Cu, Zn superoxide dismutase activity in erythrocytes were investigated in 138 healthy children and in 35 children with cancer. The mean zinc concentration in the erythrocytes of healthy children was found to be age-dependent. In the youngest group (children up to 1 year of age) the zinc concentration in erythrocytes is 18.8 +/- 3.4 micrograms/g Hb (5.89 +/- 1.23 mg/l packed cells), which is significantly lower than in other age groups. A strong logarithmic correlation (r = 0.327, p less than 0.0001 and r = 0.436, p less than 0.00001) was found between age and zinc concentration in erythrocytes, expressed as microgram/g Hb and as mg/l packed red cells, respectively. Cancer children were divided into two groups (neuro- and nephroblastoma). In the group of children with neuroblastoma no statistical differences in zinc concentration or enzyme activity were observed. In the patients with nephroblastoma, significantly higher zinc concentrations (p less than 0.05) were observed in erythrocytes. The changes of zinc concentration are accompanied by significant (p less than 0.02) decreases of enzyme activity. In this group of cancer children, statistically significant differences were observed in the zinc concentrations in erythrocytes (microgram/g Hb) between the second and the third stages of the disease. No correlation was observed between the concentration of zinc and enzyme activity in healthy children or in cancer children.

Hyperzincuria and hypozincemia in patients treated with cisplatin

The effect of cis-diamminedichloroplatinum (DDP) on plasma and urinary zinc was studied in fifteen patients with squamous cell carcinoma. A decrease in plasma zinc accompanied by an increase in urinary zinc excretion was observed. Pretreatment plasma or urinary zinc did not correlate with tumor size or site, nor was there a correlation between changes in these measurements and a response to therapy. The enhanced excretion of urinary zinc may be related to a decrease in amino acid resorption in the proximal tubule. It is concluded that DDP administration may result in hyperzincuria and could potentially precipitate a symptomatic zinc deficiency state.

Esophageal cancer and microelements

Epidemiological studies have identified dietary zinc deficiency, methylbenzylnitrosamine, and ethanol as factors strongly associated with an increased incidence of esophageal carcinoma in man. In addition, these studies have identified other trace elements which may also affect the incidence of esophageal carcinoma. Animal models have confirmed that dietary zinc deficiency increases the incidence of methylbenzylnitrosamine-induced esophageal carcinoma and that dietary zinc deficiency also increases the incidence of other dialkylnitrosamine-induced carcinomas. The dialkylnitrosamine carcinogens are activated by NADPH-dependent cytochrome P-450 enzymes in their target tissues. The activated methylbenzylnitrosamine methylates DNA, forming O6-methylguanine adducts. These O6-methylguanine adducts can lead to point mutations in DNA, and such mutations are known to be responsible for the induction of certain carcinogen-induced tumors. We have demonstrated that dietary zinc deficiency increased the cytochrome P-450-dependent microsomal metabolism of methylbenzylnitrosamine and dimethylnitrosamine, two members of this class of dialkylnitrosamine carcinogens, while the addition of zinc in vitro noncompetitively inhibits the microsomal metabolism of these carcinogens. We have also demonstrated that dietary zinc deficiency is associated with an increased formation of O6-methylguanine in the esophageal DNA of zinc-deficient animals treated with methylbenzylnitrosamine. This increased formation of the mutagenic DNA adduct O6-methylguanine may explain the increased incidence of dialkylnitrosamine-induced carcinomas observed with dietary zinc deficiency. Other trace elements, including molybdenum, selenium, and magnesium, may also alter the incidence of esophageal carcinoma, but studies of these elements are not as conclusive as the epidemiological and experimental studies linking dietary zinc deficiency with an increased incidence of human esophageal carcinoma.

Differential effects of retinoic acid on the in vitro growth and cell-surface glycoconjugates of 2 human head and neck squamous-cell carcinomas

As a part of an assessment of the potential use of retinoids in preventive and adjuvant treatment of HNSCC, we examined the effects of beta-all-trans retinoic acid (RA) on the growth and cell-surface glycoconjugates of 2 HNSCC cell lines. These lines, designated 1483 and 183A, were established from an untreated patient with a well-differentiated SCC of the retromolar trigone and one with a poorly differentiated SCC of the tonsil. Whereas the 1483 cells were sensitive to RA in that their anchorage-dependent growth, their colony growth on solid substratum, and their anchorage-independent growth in semi-solid agarose gel were all inhibited in a dose-dependent fashion by RA concentrations in the range between 1 nM and 10 microM, the 183A cells were not inhibited by RA. Their anchorage-dependent growth and colony formation were stimulated by RA, whereas their anchorage-dependent colony formation was not altered. Cell-surface glycoconjugates were modulated by RA in the sensitive 1483 cells but not in the 183A cells. Treatment of the 1483 cells resulted in a large increase in the cell-surface labelling of high-molecular-weight (Mr greater than 400,000) galactoglycoconjugates and sialoglycoconjugates, as well as an Mr 280,000 sialoglycoconjugate. Glycoconjugates with similar electrophoretic mobilities in polyacrylamide gels were labelled intensely on the surface of the 183A cells even before RA treatment and only minor changes were noticed in their labelling after treatment. These results demonstrate that RA can exert different effects on different HNSCC lines, and suggest that correlations might exist between responsiveness to RA and the stage of differentiation of the HNSCC, and between modulation of cell growth and enhancement of cell-surface glycoconjugate glycosylation by RA.

Peripheral blood and tumor-infiltrating mononuclear cell analysis in esophagus and head and neck cancer

We show a significantly decreased number of OKT3+ lymphocytes in the peripheral blood (PB) of cancer patients mainly due to a reduced number of OKT4 cells. OKT8 cells were also somewhat reduced. The numbers of DR+ and interleukin-2 receptor-bearing T-cells were significantly increased in patients. The tumor-infiltrating cells included OKT4+ AND OKT8+ lymphocytes. There was a significant correlation between the proportion of activated T-cells in PB and in tumor, as shown by DR and interleukin-2 receptor expression.

Esophageal zinc content in human squamous esophageal cancer

Zinc and vitamin A are known to interact, and deficiencies have been associated with carcinogenesis in experimental animals and humans. Since we previously have demonstrated decreased plasma zinc and vitamin A levels in patients with esophageal cancer, we wished to examine endoscopically obtained epithelial tissue for vitamin A and zinc content. This was not feasible for vitamin A, but using newly developed techniques for zinc analysis of small tissue samples, we measured esophageal epithelial zinc as well as plasma zinc and plasma vitamin A in 21 patients with esophageal cancer, 17 patients with esophagitis, and 12 normals. Mean plasma zinc in the esophageal cancer group (56 +/- 3 micrograms/dl) (mean +/- SEM) was significantly less than in the esophagitis group (72 +/- 5 micrograms/dl) and the normals (78 +/- 5 micrograms/dl). Mean plasma vitamin A in the esophageal cancer group (32 +/- 3 micrograms/dl) was significantly less than the esophagitis group (57 +/- 4 micrograms/dl) or the normals (58 +/- 5 micrograms/dl). There was no significant difference in tissue zinc content (measured as micrograms zinc/g wet weight of tissue, mean +/- SEM) among cancerous tissue (57 +/- 5 micrograms/g) and adjacent normal tissue (61 +/- 4 micrograms/g), esophagitis tissue (66 +/- 6 micrograms/g) and adjacent normal tissue (61 +/- 6 micrograms/g), or normal esophageal tissue (59 +/- 6 micrograms/g). We conclude that deficiencies of zinc or vitamin A may be cofactors in the induction of human esophageal cancer, but a mechanism cannot be accounted for by differences in epithelial zinc content.

Role of zinc deficiency in carcinogenesis

Zinc is a trace element required for the growth of normal and neoplastic tissues in a variety of species. Zinc deficiency is associated with alterations in the activity of zinc-dependent enzymes essential for cell replication. Dietary zinc deficiency also increases the incidence of certain tumors while decreasing the incidence of others. The mechanism by which zinc deficiency alters carcinogenesis is not fully understood. Among those tumors whose incidence is increased by dietary zinc deficiency are carcinomas induced by dialkylnitrosamines. This class of carcinogens requires microsomal cytochrome P-450 activation to be mutagenic. Zinc deficiency is known to increase the cytochrome P-450-dependent metabolism of methylbenzylnitrosamine (MBN), an esophageal carcinogen of this class. Examination of the kinetics of this reaction reveals zinc to be a direct noncompetitive inhibitor of the microsomal metabolism of MBN. Thus the lower rate of MBN metabolism by zinc-adequate versus zinc-deficient microsomes may be due to normal tissue zinc acting as a noncompetitive inhibitor of cytochrome P-450 activity in vivo. This effect of zinc on carcinogen metabolism may explain the increased incidence of nitrosamine-induced carcinomas observed with dietary zinc deficiency.

Alcohol and cancer

The cancers consistently associated with ingestion of alcohol, the head and neck cancers, are also associated with tobacco use and arise from epithelia that are in direct contact with both agents. Tobacco smoking-related cancers at sites not directly in contact with alcoholic beverages, that is, lung, bladder, and perhaps pancreas, do not consistently show a relationship to alcohol consumption, although lung and pancreatic tumors are associated in some studies. Liver cancer was thought to be strongly related to alcohol consumption on epidemiological grounds and because of its relationship to cirrhosis. As knowledge of the viral etiology of some cirrhoses has evolved and as methods to detect viruses have developed, the significant association between hepatitis B virus and hepatocellular carcinoma has become clear. Alcohol and hepatitis B virus may interact in the etiology of the disease and have important separate roles as well. There are epidemiologic and experimental data showing that malnutrition (resulting from poor food choice), economic deprivation, or alcoholism contributes to the risk for head, neck, and liver cancers. Colon cancers occur about equally in men and women, are found in well-nourished populations, and are not associated with tobacco smoking. Rectal cancers show a preponderance of cases in men but are frequently found in women as well and are not thought to be associated with smoking or malnutrition. The association between colorectal cancers and alcohol consumption, when it is found, apparently occurs at even relatively low alcohol intakes and is often stronger for consumption of beer than of other beverages. Nutritional and metabolic mechanisms proposed for the influence of alcohol on carcinogenesis are supported by studies in human subjects and laboratory animals. Animal models are needed in which effects of ethanol on carcinogenesis can be consistently demonstrated and which can then be used to examine mechanisms.

Copper, zinc and copper/zinc ratio in chronic pancreatitis and pancreatic cancer

Serum copper and zinc levels and their ratio were evaluated in 48 control subjects, 29 patients with pancreatic cancer, 46 with chronic pancreatitis and 32 with extra-pancreatic diseases, with the purpose of ascertaining modifications in chronic pancreatic disease. Hepatic involvement and age were also investigated as possible factors influencing results. Cu/Zn ratio was found to be significantly increased in pancreatic cancer (2.66 +/- 0.16, mean +/- SE) as compared to controls (1.39 +/- 0.06, p less than 0.001), chronic pancreatitis (1.82 +/- 0.09. p less than 0.001) and extra-pancreatic diseases (1.81 +/- 0.18, p less than 0.001), but without practical clinical value. Serum zinc levels appear to decrease with age, while copper and Cu/Zn ratio increase. However, covariance analysis demonstrated that age does not play an important role in influencing copper and Cu/Zn ratio. A decreased liver synthetic function, at least in part age-related, seems to be an additional factor in decreasing serum zinc values.

Altered vitamin A-binding proteins in carcinoma of the head and neck

Since vitamin A inhibits the terminal differentiation of keratinocytes, elevated levels of cytoplasmic vitamin A-binding proteins could explain the reduced tendency of squamous cell carcinomas to undergo terminal differentiation. The levels of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP) were determined in 37 squamous cell carcinomas of the head and neck and were compared with the corresponding levels in adjacent normal tissue. The CRBP levels expressed per milligram of DNA were increased threefold (P = 0.0005) in the tumor as compared with normal tissue. In contrast, CRABP levels expressed per milligram were decreased 2.5-fold (P = 0.0007) in the tumor as compared with normal tissue. Despite significant differences in retinoid-binding protein levels between tumor and adjacent normal tissue, there was no significant correlation of these differences with any of the patient clinical parameters or any of the tumor growth characteristics. The increased CRBP levels may explain why terminal differentiation, an important mechanism for limiting growth in normal keratinocytes, is less readily induced in squamous cell carcinomas.

The use of epidemiology, scientific data, and regulatory authority to determine risk factors in cancer of some organs of the digestive system. 2. Esophageal cancer

The epidemiologic aspects of esophageal cancer are well known. The extreme geographical variations in incidence of the disease, the variability in the sex ratio, and the secular trends have been described frequently. The etiology of cancer of the esophagus is known to be complex and composed of multiple factors, those caused by the environment being of greatest importance. The disease preferentially attacks groups with a low socioeconomic status or those hindered by poverty. The esophageal cancer belt has been frequently studied to provide clues to the etiology of esophageal cancer but no definite culprit has yet been found. The majority of the factors so far implicated in cancer of the esophagus appear to act directly on the esophagus rather than systemically. This is an unusual situation in that it enables the disease to be prevented by primary means. There appears to be an enormous disparity in the etiology of the disease among various countries. This disparity may be more apparent than real if the epidemiologic data are interpreted to mean that there is a two-stage process involved, with multiple etiologies for each stage. If we assume that nutritional deficiencies, even subtle ones, predispose the esophagus to influence by carcinogenic substances, the geographic differences fade. Nutritional deficiencies can develop by chronic alcohol use as well as by poverty and lack of an adequate food supply, but diet does not explain the whole picture. External carcinogens are necessary to effect the end result. The culprit may be tobacco in one culture and fungal elements in another. The South African studies which showed an association with tobacco and not alcohol could be explained if we assume that the population's nutritional deficiencies already predisposed the esophagus for the effect of an external carcinogen, thereby making alcohol usage superfluous. It would be helpful if the relationship between esophagitis and nutritional status were elucidated and if it were determined that the condition could be improved or eliminated by dietary factors. The association between nutrition and esophagitis may suggest methods of primary prevention of esophageal cancer and provide a chance of lowering the incidence of this deadly disease.

Nutritional status of patients with untreated cervical cancer. II. Vitamin assessment

Prospective vitamin assessment was undertaken in 78 patients with untreated cancer of the uterine cervix. At least one abnormal vitamin level was present in 67% of patients while individual levels were abnormal in as many as 38% of patients. Significantly lowered levels of plasma folate, vitamin A, and vitamin C were present. Although most of these vitamins did not correlate with other parameters of protein-calorie malnutrition, the possible preventative and treatment effects of these vitamins require additional investigation.