Esophageal adenocarcinoma (EAC) has been rapidly increasing in Western countries during the past half century, especially in white men. Esophageal squamous cell carcinoma (ESCC) used to be the dominant type of esophageal malignancy both in Western and Asian countries. The rapid increase of EAC in Western countries has occurred in parallel with an increased prevalence of gastroesophageal reflux disease (GERD) and its major determinant, obesity. Such an increase in EAC has not yet been observed in Asia, despite a recent increase in prevalence of GERD. In this mini-review, we analyze possible factors influencing such east-west ('Orient to Occident') differences, particularly possible roles of ethnicity and environmental factors, such as Helicobacter pylori infection and nutritional factors, and how these might interact with socioeconomic differences. Development of Barrett's esophagus and esophageal adenocarcinoma appears to be strongly affected by ethnic factors, with populations resident at the west end of the Eurasian continent, such as Anglo-Celtics, being more prone to both conditions. On the other hand, ethnic groups from the eastern and southern ends of Eurasia, such as Chinese, Koreans and Japanese, and Africans might be more prone to developing esophageal squamous cell carcinoma. Future trends will also be discussed.

Chronic pancreatitis (CP) is a continuing or relapsing inflammatory disease of the pancreas. Several studies have demonstrated that mutations in the cationic trypsinogen (PRSS1) gene and the cystic fibrosis transmembrane conductance regulator (CFTR) gene are causative of the pathogenesis in a subset of hereditary and/or idiopathic CP cases. Recently, the N34S alteration of the pancreatic secretory trypsin inhibitor (PSTI) gene has been suggested to be closely associated with the pathogenesis of hereditary and/or idiopathic CP. Herein we analyzed genetic alterations of the PSTI gene in 32 unrelated Japanese CP patients who developed juvenile-onset CP or had a family history of CP; 5 patients were found to harbor alterations in this gene. In 3 of these 5 patients, heterozygous N34S alterations were found; this frequency is significantly lower than that in Caucasian patients reported previously. Moreover, a novel homozygous G-to-A transition in the promoter region of PSTI at 215 bp upstream from the translation initiation site (Ϫ215GϾA) was observed in 2 patients. We further surveyed the Ϫ215GϾA alteration in 117 normal individuals; none of these individuals harbored this alteration. Our results suggested that the Ϫ215GϾA alteration, as well as the N34S alteration, is a predisposing factor for CP.

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Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase (PAH) in the liver. Patients with PKU show increased L-phenylalanine in blood, which leads to mental retardation and hypopigmentation of skin and hair. As a step toward gene therapy for PKU, we constructed a replication-defective, E1/E3-deleted recombinant adenovirus harboring human PAH cDNA under the control of a potent CAG promoter. When a solution containing 1.2 x 10(9) plaque-forming units of the recombinant adenovirus was infused into tail veins of PKU model mice (Pah(enu2)), predominant expression of PAH activity was observed in the liver. The gene transfer normalized the serum phenylalanine level within 24 h. However, it also provoked a profound host immune response against the recombinant virus; as a consequence, the biochemical changes lasted for only 10 d and rechallenge with the virus failed to reduce the serum phenylalanine concentration. Administration of an immunosuppressant, FK506, to mice successfully blocked the host immune response, prolonged the duration of gene expression to more than 35 d, and allowed repeated gene delivery. We noted a change in coat pigmentation from grayish to black after gene delivery. The current study is the first to demonstrate the reversal of hypopigmentation, one of the major clinical phenotypes of PKU in mice as well as in humans, by adenovirus-mediated gene transfer, suggesting the feasibility of gene therapy for PKU.

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