LIFE09200604007 Tabish - Homi Bhabha National Institute
LIFE09200604007 Tabish - Homi Bhabha National Institute
LIFE09200604007 Tabish - Homi Bhabha National Institute
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Review of Literature<br />
of 31 published case-control associations of GSTT1 null genotype along with GSTM1<br />
null genotype with head and neck cancer risk was observed 149 . Apart from this, in<br />
Indian population as well GSTT1 null genotype has emerged as associated with risk of<br />
upper aero digestive tract cancers 143, 150 . On the contrary a large Indian study has<br />
shown GSTT1 to be significantly protective in oral cancer patients with tobacco habit<br />
151 .<br />
GSTP1 (Glutathione-S-Transferase-Pi 1)<br />
The gene encodes an enzyme belonging to GST pi class. GSTP1-exon5<br />
Ile 105 Val polymorphism is extensively studied in terms of association with cancer 152 .<br />
This polymorphism is reported to confer risk of upper aero digestive tract cancers<br />
among Indians along with other GSTT1 and GSTM1 polymorphism 153 . In addition<br />
GST profile may have a prognostic value since it is associated with the response to<br />
therapy in human malignancies 148, 154, 155 . GSTP1 Ile 105 Val polymorphism is found to<br />
be associated with modestly increased risk of second primary malignancy after index<br />
head and neck squamous cell carcinomas 44 .<br />
SULT1A1 (Sulfotransferase 1A1)<br />
The gene encodes sulfotransferase enzyme that belongs to phase II carcinogen<br />
detoxifying enzyme category. It catalyzes the sulfate conjugation of many hormones,<br />
neurotransmitters, drugs, and carcinogenic compounds resulting in increased polarity<br />
and solubility of the compound that facilitates excretion of carcinogens through bile or<br />
urine. SULT1A1-exon7 Arg 213 His polymorphism is very extensively studied and is<br />
found to be associated with head and neck cancer and lung cancer risk 156, 157 . Our study<br />
of meta-analysis of 33 case control studies showed His/His 213 genotype to confer<br />
significant risk UADT cancers 12 .<br />
MPO (Myeloperoxidase)<br />
It activates wide range of tobacco smoke procarcinogens such as<br />
benzo[a]pyrene and aromatic amines into activated carcinogens. The -463G>A SNP<br />
occurs in the MPO promoter region leading to decreased expression and activity 158 .<br />
The variant allele of MPO is shown to have mixed effect on cancer risk. It is reported<br />
that subjects bearing the A/G or A/A allele have a reduced risk to suffer from advanced<br />
lung cancer and esophageal cancer 159, 160 . Where as in other reports genetic effect of<br />
48