Dietary intake and the risk of malignant mesothelioma

Malignant Mesothelioma of the Pleuraand Other Malignancies in the Same Patient

Aims and background

The co-existence of mesothelioma, mostly asbestos-related, and other primary malignancies has repeatedly been reported. The present study evaluated the frequency of such an occurrence.

Methods

In the period October 1979-June 2002, 215 cases of malignant pleural mesothelioma were diagnosed at the Hospital of Monfalcone, Italy. All the cases of the above series, examined at necropsy (169), were included in the study. Occupational histories had been obtained from the patients or from their relatives by personal or telephone interviews. In 132 cases, asbestos bodies were isolated after chemical digestion of lung samples. The thoracic cavities were examined for pleural plaques.

Results

Additional malignancies were observed in 32 cases (18.9%). Multiple tumors were synchronous in 22 cases, metachronous in 8 cases, and synchronous and metachronous in 2. Four different tumors were found in 2 cases, 3 malignancies were detected in 6 patients, and 2 malignancies in the remaining 24. The most frequent additional malignancies were prostate adenocarcinoma (7 cases), non-Hodgkin lymphoma or chronic lymphocytic leukaemia (5 cases), bladder carcinoma (4 cases), kidney carcinoma (4 cases), large bowel carcinoma (4 cases), and liver cell carcinoma (4 cases). All the patients had histories of exposure to asbestos, mostly in shipbuilding. Lung asbestos body burdens ranged between 60 and 230,000 per gram of dried tissue. Pleural plaques were found in 26 cases.

Conclusions

In contrast with other series of the literature, in the present cases the co-existence of mesothelioma and other malignancies appeared as a relatively frequent event. The lack of a control group does not allow definite conclusions about the meaning of the occurrence. However, the co-existence of certain tumors with asbestos-related mesothelioma suggests that mesothelioma and associated malignancies might share some etiologic factors (asbestos and others).

Risk of occupational exposure to asbestos, silicon and arsenic on pulmonary disorders: Understanding the genetic-epigenetic interplay and future prospects

BACKGROUND

Epidemiological studies suggest strong association of lung disorders with occupational exposure to asbestos, silicon and arsenic. The chronic occupational exposure primarily through inhalation results in adverse outcome on the respiratory tract which may also be fatal. Although several mechanisms have attributed towards these diseases; the molecular pathogenesis is still unknown.

OBJECTIVE

In this review, we investigated the plausible molecular mechanism based on current research that may identify the genetic and epigenetic susceptibility of respiratory disorders upon such occupational exposures in humans.

METHODS

We considered genetic variants and epigenetic alterations associated with pulmonary exposure hazards leading to asbestosis, silicosis and arsenicosis. Our review is stringently based on the literatures available through peer-reviewed articles mostly published in the last 10 years. Relevant search were conducted using keywords like "occupational lung disorders" along with "asbestos", "silicon" and "arsenic".

RESULTS

Till September 2015, pubmed search yielded approximately 780 articles relating to asbestos exposure; 240 articles for silicon exposure and 60 articles for arsenic exposure. Extensive screening for genetic and epigenetic factors identified certain genes and related pathways that are important to determine the susceptibility of an individual towards such occupational exposure.

CONCLUSION

The link between genotype and phenotype and its association with disease susceptibility is very complex in nature due to several factors like person's environment, lifestyle and nutritional status. The epigenome is dynamic as well as reversible and can be reshaped further by certain dietary components throughout its life. In the present review, we have addressed the role of molecular pathogenesis of occupational lung diseases based on the genetic variability and epigenetic alterations and also attempted to highlight the promising aspect of dietary interventions to counter toxic outcomes upon occupational exposure to asbestos, silicon or arsenic.

Malignant pleural and peritoneal mesothelioma consequential to brief indirect asbestos exposure

This report highlights that pleural and peritoneal mesothelioma can occur without direct asbestos exposure as was seen in our young patient. The patient had indirect exposure for as short as 3 months as a child, 15 years earlier, when she was residing with her miner father in the district of Jharia, Jharkhand, which is an asbestos-rich mining area in eastern India. The patient presented with chest pain and breathlessness. Chest X-ray showed opaque right hemithorax. Typical contrast- computed tomography (CECT) enhanced radiological features included nodular, soft-tissue attenuation and homogenously enhancing rind-like mass causing scalloping of the underlying lung and liver. Similar lesions were also found involving the pelvis. Diagnosis of malignant mesothelioma was confirmed on lung biopsy. Under-reporting of exposure is usual because it is unrecognized by both patients and investigators.

Familial aggregation of malignant mesothelioma in former workers and residents of Wittenoom, Western Australia

Clustering of cases of malignant mesothelioma within families has often been observed, but disentangling genetic and exposure effects has not been done. Former workers and residents exposed to crocidolite at Wittenoom, Western Australia, where many families shared exposure to asbestos, have had high rates of mesothelioma. Our study aimed to estimate the additional risk of mesothelioma in relatives, after allowance for common exposure to crocidolite. More than 11,000 former asbestos workers and residents from Wittenoom have been followed up in cancer and death registries. Levels of exposure for all members of the Wittenoom cohorts have been estimated previously. Relationships between family members of all mesothelioma cases were established from questionnaires, birth and death certificates. Expected numbers of cases of mesothelioma were estimated by fitting a Weibull survival model to all data, based on time from first asbestos exposure, duration and intensity of exposure and age. For each family group, the earliest case was considered the index case. Predicted risk was estimated for each subject from the time of diagnosis of the index case. Familial risk ratios were estimated by dividing observed cases by the sum of risks of all same degree relatives of index cases. There were 369 family groups with at least one case of mesothelioma and a further 25 cases of mesothelioma among relatives in the same families, with 12.9 expected. The risk ratio for blood relatives was 1.9 (95% confidence interval [CI] = 1.3-2.9, p = 0.002). These findings suggest an important, but not large, genetic component in mesothelioma, similar to many other cancers.

Factors that impact susceptibility to fiber-induced health effects

Asbestos and related fibers are associated with a number of adverse health effects, including malignant mesothelioma (MM), an aggressive cancer that generally develops in the surface serosal cells of the pleural, pericardial, and peritoneal cavities. Although approximately 80% of individuals with MM are exposed to asbestos, fewer than 5% of asbestos workers develop MM. In addition to asbestos, other mineralogical, environmental, genetic, and possibly viral factors might contribute to MM susceptibility. Given this complex etiology of MM, understanding susceptibility to MM needs to be a priority for investigators in order to reduce exposure of those most at risk to known environmental carcinogens. In this review, the current body of literature related to fiber-associated disease susceptibility including age, sex, nutrition, genetics, asbestos, and other mineral exposure is addressed with a focus on MM, and critical areas for further study are recommended.

Lycopene in cancer prevention and treatment

Dietary intake of lycopene is inversely associated with the risk of many cancers. Preclinical studies show that lycopene has potent in vitro and in vivo antitumor effects, suggesting potential preventive and therapeutic roles for the compound. However, clinical trials with lycopene have only recently been started, and available clinical data preclude firm conclusions with regard to its use in cancer prevention and treatment. Further mechanistic studies and randomized controlled clinical intervention trials with lycopene involving cancer patients are warranted.

Malignant mesothelioma: global incidence and relationship with asbestos

Mesothelioma incidence varies markedly from one country to another. The highest annual crude incidence rates (about 30 cases per million) are observed in Australia, Belgium, and Great Britain. A lot of data indicate a relationship between mesothelioma and asbestos. The hot areas for mesothelioma exactly correspond to the sites of industries with high asbestos use, such as shipbuilding and asbestos-cement industry. However, in many countries with high asbestos consumption, mesothelioma incidence is low. The reasons for this fact are not clear. The latency periods elapsing between first exposure to asbestos and development of mesothelioma are mostly longer than 40 yr. An inverse relationship exists between intensity of asbestos exposure and length of the latency period. Mesothelioma generally develops after long-time exposures to asbestos. Some recent studies show that the risk increases with the duration of exposure. Possible co-factors in the pathogenesis of asbestos-related mesothelioma include genetic predisposition, diets poor in fruit and vegetables, viruses, immune impairment, recurrent serosal inflammation. The study of co-morbidity in mesothelioma could give an insight into the pathogenesis of the tumor. While a levelling-off in mesothelioma incidence has been registered in some countries, a worsening of the epidemic is predictable in large parts of the world.

Botanical medicine and cancer: a review of the safety and efficacy

It is currently estimated that > 50% of all patients diagnosed with cancer explore complementary and alternative medicine - especially herbal medicine. We conducted a comprehensive review to assess the safety and efficacy of herbal medicines commonly used by patients in an attempt to: prevent cancer; treat cancer; and treat adverse effects associated with conventional cancer treatments. Current evidence suggests that Asian ginseng, garlic, green tea, tomatoes and soy intake as part of the diet may be useful in preventing various cancers; additional research is needed in order to determine the efficacy of essiac, evening primrose oil, mistletoe, reishi, shiitake and turmeric as cancer treatments; and ginger may be effective in treating chemotherapy-induced nausea and vomiting.

Lycopene and the lung

The human lung, due to the oxidative and ozone stress to which it is exposed, is particularly vulnerable to oxidative damage. Concentrations of dietary antioxidants in the lung epithelial lining and lining fluids may provide protection against oxidative damage. A randomized clinical trial was conducted to study the effects of supplemental, carotenoid-rich vegetable juice (V-8) on lung function macrophage levels of carotenoids and in moderating ozone-induced lung damage. Healthy young adults (n = 23) were exposed to 0.4 ppm ozone in a chamber for 2 hr after either 2 weeks of antioxidant supplementation (including one can of V-8 juice daily) or placebo. Mean lung concentrations of lycopene increased by 12%, and lung epithelial cell DNA damage as measured by the Comet Assay decreased 20% in supplemented subjects. No change in peripheral blood lymphocyte DNA damage was observed as evidenced by no change in mean comet area or length in supplemented or placebo subjects. We were not able to separate the effects of lycopene from other carotenoids or antioxidants administered in this study; however, lycopene is the predominant carotenoid in V-8 (it represents 88% of total carotenoids). A review of the epidemiologic literature providing evidence for the effect of lycopene (diet or serum) or tomatoes on the risk of lung cancer reveals 27 observational epidemiologic studies (18 case-control and nine cohort studies) reporting relative risk (RR) estimates. RR estimates for cohort studies ranged from 0.63 to 1.24 (mean RR = 0.93, SD = 0.16). Odds ratios (OR) for case-control studies ranged from 0.27 to 0.93 (mean OR = 0.61, SD = 0.16). Both plasma levels (RR = 1.01, OR = 0.37) and estimated intakes of lycopene from dietary sources (mean RR = 0.93, RR range = 0.80-1.05; mean OR = 0.67, OR range = 0.27-0.93) were examined. Seventeen studies, three of which were cohorts, reported their results at the level of tomato consumption rather than, or in addition to, lycopene consumption (mean RR = 0.89, RR range = 0.63-1.24; mean OR = 0.61, OR range = 0.37-0.80). The published epidemiologic literature shows an interaction between study design and the relationship between lycopene and/ or tomatoes and risk of lung cancer. Overall, cohort studies did not show an association, whereas case-control studies showed a decreased risk with greater consumption of lycopene and tomatoes. Although lycopene can be found in the human lung, and there is evidence, albeit weak, for a protective association with lung cancer, its biologic role remains to be elucidated.

Occupation and risk of malignant pleural mesothelioma: A case-control study in Spain

BACKGROUND

The association of mesothelioma and asbestos exposure is well known, but some data suggest that probably many people are still being exposed to asbestos without knowing it.

METHODS

Between 1993 and 1996, 132 cases (77% males) of histologically confirmed malignant pleural mesothelioma and 257 controls, residents in two provinces of Spain (Barcelona and C¿adiz), were interviewed. They were classified according to their probability and intensity of occupational asbestos exposure by a panel of industrial hygienists, based on a detailed occupational history.

RESULTS

Age and sex-adjusted odds ratio (OR) for the highest probability of exposure to asbestos was 13.2 (95% confidence interval 6.4-27.3), and 27.1 (9. 28-79.3) for high intensity. A dose-response trend was observed for both, probability and intensity. Overall, 61% of cases and 42% of controls had ever worked in an occupation with risk of asbestos exposure, with an OR of 2.59 (1.60-4.22). In our population 62% of cases could be attributed to occupational asbestos exposure.

CONCLUSIONS

A high risk of pleural mesothelioma due to occupational asbestos exposure is confirmed, but there is still a sizeable proportion for which no evidence of occupational exposure was found. Most of these cases could be due to other sources of asbestos exposure, mainly domestic or environmental.

Mesothelioma: cases associated with non-occupational and low dose exposures

OBJECTIVES

To estimate the importance of low dose exposure to asbestos on the risk of mesothelioma.

METHODS

A review of the literature.

RESULTS AND CONCLUSIONS

There is no evidence of a threshold level below which there is no risk of mesothelioma. Low level exposure more often than not contains peak concentrations which can be very high for short periods. There might exist a background level of mesothelioma occurring in the absence of exposure ot asbestos, but there is no proof of this and this "natural level" is probably much lower than the 1-2/million/year which has been often cited.

Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature

The epidemiologic literature in the English language regarding intake of tomatoes and tomato-based products and blood lycopene (a compound derived predominantly from tomatoes) level in relation to the risk of various cancers was reviewed. Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites. About half of the relative risks for comparisons of high with low intakes or levels for tomatoes or lycopene were approximately 0.6 or lower. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix. Because the data are from observational studies, a cause-effect relationship cannot be established definitively. However, the consistency of the results across numerous studies in diverse populations, for case-control and prospective studies, and for dietary-based and blood-based investigations argues against bias or confounding as the explanation for these findings. Lycopene may account for or contribute to these benefits, but this possibility is not yet proven and requires further study. Numerous other potentially beneficial compounds are present in tomatoes, and, conceivably, complex interactions among multiple components may contribute to the anticancer properties of tomatoes. The consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption.