Abstract
Adenosine Deaminase (ADA) is a polymorphic enzyme that degrades irreversibly adenosine to inosine and is present in cell cytoplasm and in interstitial fluid was it acts as ecto-ADA. Ecto-ADA shows also extra-enzymatic activity acting as co- stimulatory molecule of adenosine receptors .Adenosine is a purine nucleoside that hasan important role in cancer development.In solid tumors high level of this substance is determined by hypoxia resulting in inhibition of T cell killer activation . We have recently found an association between colon cancer and ADA genetic polymorphism. We studied three polymorphic sites ADA1, ADA2 and ADA6 and found that ADA1 *2/ ADA2 *1 haplotype is more represented, while ADA1 *2/ ADA2 *2 is less represented in cancer than in controls. ADA2 *2/ ADA6 *2 is less represented in patients than in controls. The present note reports a study in endometrium cancer. We have studied 70 women with endometrium cancer from the White population of Rome.Data on 109 subjects with colon cancer and on 246 blood donors reported in a previous paper are also shown. The three polymorphisc sites of ADA gene (ADA1, ADA2 and ADA6) were analyzed. Genotypes were determined by RFLP-PCR. Statistical analyses were carried out by SPSS package. Haplotype frequencies are maximum likelihood estimates. No statistically significant difference is observed in the distribution of ADA haplotypes between the two cancers. In both cancers ADA1 *2/ ADA2 *1 haplotype is more represented while ADA1 *2/ ADA2 *2 is less represented than in controls. ADA2 *2/ ADA6 *2 haplotype is less represented in both cancers than in controls. A border line difference between the two classes of cancers is observed in the distribution of ADA1/ADA6 haplotypes. The present study was suggested by the following: i) High levels of adenosine in cancer inhibits T cell killer activation, ii) ADA contributes to control level of adenosine, iii) Polymorphic sites of ADA may influence extraenzymatic function of ecto-ADA. Our data confirm the association observed between ADA and colon cancer making unlikely the possibility of a mere sampling chance artifact and suggest that genetic polymorphisms within the ADA gene may have an important role in susceptibility to cancer.
Highlights
IntroductionHigh level of adenosine is determined by hypoxia in solid tumors resulting in inhibition of T cell killer activation [1]
Adenosine is a purine nucleoside that hasan important role in cancerdevelopment of
The present observation confirms the association observed between adenosine deaminase (ADA) and colon cancer making unlikely the possibility of a mere sampling chance artifact
Summary
High level of adenosine is determined by hypoxia in solid tumors resulting in inhibition of T cell killer activation [1]. The intra and extra cellular concentration (about 100 nM) of adenosine is controlled by adenosine deaminase (ADA) and adenosine kinase activities. Adenosine deaminase (ADA) is a polymorphic enzyme that degrades irreversibly adenosine to inosine and is present in cell cytoplasm and in interstitial fluid was it acts as ecto-ADA. Ecto-ADA shows extra-enzymatic activity acting as co- stimulatory molecule of adenosine receptors [2]. The polymorphism of ADA was discovered by Spencer et al [3] and is due to the presence of two codominant alleles ADA1*1 and ADA1*2 at an autosomal locus. There are three phenotypes ADA11, ADA121, ADA12 with enzymatic activity decreasing in the order ADA11>ADA121>ADA12
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