Barrett's esophagus

Association between pulmonary mycobacterium avium complex infection and lung cancer

INTRODUCTION

Patients with lung cancer are sometimes found to have respiratory cultures growing Mycobacterium avium complex (MAC). This study describes the clinical, pathologic, and radiographic -characteristics of individuals who harbor concomitant lung cancer and MAC.

METHODS

Retrospective analysis of patients with positive respiratory cultures for MAC (370 men, 475 women) and with newly diagnosed lung cancer (792 men, 840 women) from 1995 to 2010.

RESULTS

Of the patients with respiratory cultures growing MAC, 8.6% of men and 6.3% of women had lung cancer. Twenty-five percent of patients with lung cancer and 3% with nonbronchiectatic benign lung disease grew MAC from their respiratory cultures. Significantly fewer women with both MAC and lung cancer were smokers than the control group of women with lung cancer and negative MAC cultures (68% versus 89%, p < 0.01). Squamous cell carcinoma occurred in 40% of women in the MAC/lung cancer group versus 28% of women in the lung cancer control group. Peripherally located squamous cell carcinomas were found in 71% of the MAC/lung cancer group versus 40% of the lung cancer control group (p = 0.01)

CONCLUSIONS

The percentage of smokers among women with both MAC and lung cancer was lower than among the lung cancer control group who did not grow MAC. The presence of MAC in respiratory cultures of lung cancer patients was particularly associated with squamous cell carcinomas located in the periphery of the lung. Because MAC typically affects distal airways, this possible association between MAC infection and lung cancer warrants further study.

Regulation of CDX2 expression in esophageal adenocarcinoma

Reflux of acidic gastric contents and bile acids into the lower esophagus has been identified to have a central role in esophageal malignancy and is reported to upregulate caudal-related homologue 2 (CDX2), a regulatory gene involved in embryonic development and axial patterning of the alimentary tract. The aim of this study was to characterize the expression of CDX2 in a well-defined series of human esophageal tissues, comprising reflux-induced esophagitis, premalignant Barrett esophagus (BE), and primary esophageal adenocarcinoma (EADC). To explore potential molecular regulatory mechanisms, we also studied the expression of beta-catenin, SOX9, and CDX2 promoter methylation in esophageal tissues, in addition to the effect of bile acids and nitric oxide (NO) on CDX2 expression in the normal human esophageal cell line Het1A. Relative to matched normal esophageal epithelia, CDX2 was overexpressed in esophagitis (37% for RNA; cytoplasmic immunoreactivity in 48% of tissues), a high proportion (91%) of BE tissues, and in EADC (57% for RNA; cell nuclear immunopositivity in 80%). An association with beta-catenin expression was seen, but not with SOX9 or CDX2 promoter methylation. In Het1A cells, CDX2 was upregulated following exposure to bile acids and NO, alone and in combination. These results further implicate CDX2 and beta-catenin in the molecular pathogenesis of human EADC. The observed synergistic effect of NO on the efficacy of bile acid-induction of CDX2 suggests a novel role for NO in modulating the development of the Barrett phenotype and esophageal adenocarcinogenesis.

Physical activity, obesity and risk for esophageal adenocarcinoma

Over the past three decades, an increasing incidence of esophageal adenocarcinoma (EADC) has been reported throughout North America and Europe at a rate exceeding that of any other human solid tumor. Recent studies have clearly implicated chronic gastroesophageal reflux disease and several lifestyle risk factors, including tobacco consumption, diet and obesity, to be associated with increased risk of EADC. Although physical inactivity is now recognized as a risk factor for several chronic diseases including cancer, only a very limited number of studies have specifically evaluated the association between physical activity and esophageal malignancy. Furthermore, the precise biological mechanisms underlying the association between physical activity, obesity and cancer risk remain unclear. Since successful promotion of healthy body weight and exercise may substantially reduce the future incidence of cancer in the population, the purpose of this review is to explore current evidence linking physical activity, obesity and risk of malignancy – specifically EADC.

A polymorphic variant of the insulin-like growth factor type I receptor gene modifies risk of obesity for esophageal adenocarcinoma

BACKGROUND

To investigate potential biologic mechanisms underlying the association between obesity and risk for esophageal adenocarcinoma (EADC), we studied the frequency of a common polymorphism of the insulin-like growth factor I receptor (IGF-IR) gene in patients with either gastroesophageal reflux disease (GERD), premalignant Barrett esophagus (BE) and or invasive EADC.

METHODS

Using a well characterized series of 431 individuals enrolled in a case-control study, we studied the frequency of the IGF-IR gene polymorphism, G1013A.

RESULTS

On multivariate analysis controlling for age and gender, in comparison to asymptomatic controls, obese individuals with the polymorphic A-variant (G/A, A/A) were found to have significantly increased risk for EADC (OR 4.81; 95%CI 1.09-21.15), whereas obese individuals with the G/G variant were not at statistically significant increased risk (OR 2.69; 95%CI 0.41-17.62). Similarly, compared to asymptomatic controls, only obese individuals with the A-variant (G/A, A/A) were at increased risk for BE (OR 3.11; 95%CI 1.12-8.63), while obese individuals with the G/G variant were not at increased risk for BE (OR 2.91; 95%CI 0.69-12.15).

CONCLUSION

We conclude that the common IGF-IR gene polymorphism G1013A modulates the risk of obesity for EADC, an effect most likely mediated by altered the receptor function by influencing gene transcription or mRNA stability. These findings further implicate the insulin-like growth factor axis in the molecular pathogenesis of EADC, and represent a plausible mechanistic link underlying the association between obesity and malignancy.