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==== Studies on Genetic Alteration in Cancers Prevalent in Thailand ====
  	
      
The central goal of the project is to gain an understanding 
of the molecular changes that will lead to the development of 
various types of cancer. Tumors of the esophagus, liver 
(hepatocellular carcinoma, cholangiocarconoma), hematopoietic 
system (malignant lymphoma) and cervix are becoming prevalent 
in Thailand, with geographical variations in their occurrence 
probably reflecting differences in etiology. The collaborative 
studies between the laboratory and the International agency for 
Research on Cancer (IARC) will examine the frequency of mutations 
in cancer cases (particularly in cell control genes), selected 
on the basis of pathology and clinical stage. The aim is to 
examine in properly planned epidemiological studies the role of 
genetic alterations in the etiology, pathogenesis, diagnosis and 
prognosis of these cancers

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=== Nasopharyngeal carcinoma (NPC) ===
 
Nasopharyngeal carcinoma (NPC) is an endemic cancer with a male 
to female ratio about 2-3:1. The high endemic areas include 
Southern China, Greenland and Alaska . The annual incidence of 
NPC varies from less than 1 per 100,000 population in non-endemic 
area to 19 cases per 100,000 population in highly endemic areas. 
Thailand has an incidence rate of 5 cases per 100,000 population 
with this cancer being one of the ten most prevalent in males and 
particularly in the Chinese ethnic population. 

Epstein Barr Virus (EBV) infections, dietary and environmental 
factors e.g. consumption of salted fish and meat have been found 
to be associated with the disease. Occupational hazards including 
exposure to formaldehyde, dust and certain aromatic hydrocarbons 
have been determined as possible risk factors for NPC. Genetic 
factors and alcohol consumption have also been determined as possible 
risk factors for this type of cancer. However, the molecular events 
leading to the development of the tumor are still not well understood. 

In this study, we analysed p53 mutations from NPC patients in Chiang Mai 
and Bangkok provinces to determine whether they correlated with the 
incidence of NPC.
 
    
=== Esophageal Cancer  ===

Cancer of esophagus can be classified into squamous cell carcinoma (SCC) 
and adenoma (ADC). It ranks among one of the ten most frequent cancers 
in the world and is prevalent in developing countries. 

It has been shown that the analysis of genetic alterations, particularly 
of p53 gene mutations in ADC and SCC are different in molecular level. 
Such differences reflect not only the involvement of distinct causative 
agents and mutational mechanisms but also the existence of distinct cell 
type specific pathways towards the expression of malignant phenotypes 
and tumor progression. It is believed that exposure to both tobacco 
and alcohol is associated with p53 in SCC whereas in ADC, p53 may result 
from the complex interplay between exogenous factors and endogenous biological 
processes. 

In Thailand, the occurrence of esophageal cancer seems to be prevalent only 
in the Southern part of the country. The etiology of the disease is still 
unclear but may be related to exposure to specific carcinogens and promoters 
through food and the environment. 

The laboratory studies the genetic alteration in esophageal cancer in populations 
in different parts of Thailand and elucidates the risk factors involved in the 
development of this type of cancer.
 

==== Evaluation of new cancer chemopreventive agents from Thai medicinal plants ====

Chemoprevention is the process of inhibiting, delaying or reversing carcinogenesis 
in the premalignant phase. The activities of chemopreventive agents include 
antiproliferative, anti-inflammatory, antimutagenic and antioxidant mechanisms 
as well as induction of apoptosis and cell proliferation. Currently, a variety 
of natural products and synthetic chemicals have been found to possess 
chemopreventive properties. 

The Laboratory of Chemical Carcinogenesis in collaboration with the laboratory 
in Natural Products and the German Cancer Research Center has initiated a project 
that aims at identification isolation and characterization of Thai medicinal 
plants that may be useful in chemoprevention cancer. Screening for chemopreventive 
properties in potential candidates can be achieved using both in vitro bioassays 
and in vivo testing systems. Selections of plants are made on the basis of their 
traditional use in treatments of cancer and other ailments

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