LIFE09200604007 Tabish - Homi Bhabha National Institute

Discussion
assess UADT MPN risk, by developing a genotype-phenotype correlation. It is believed
that patients with MPN provide a genetically enriched resource of risk alleles and hence
are ideal to study predisposition to cancer 200 . The correlation observed in the present
study supports the notion that inherent deficiencies in response to carcinogen-induced
DNA damage/repair, apoptosis and cell cycle control may contribute to the risk of
developing UADT MPN and the risk is modulated by genetic polymorphisms in genes
regulating these cellular events. Similar hypothesis has been tested by other groups in
order to investigate the functional significance of genetic polymorphisms in conferring
cancer risk by modulating intermediate phenotypes 49, 51, 52, 54, 55, 201 . These studies were
conducted on patients with mostly lung cancer and also breast cancer and head and
neck cancers and correlated polymorphism in either single gene or genes falling in
single pathway, with occurrence of cancer.
Generation of Lymphoblastoid cell lines
One of the prime requisites for such long term genotype-phenotype correlation
studies is the continuous supply of staring material. Therefore, we successfully
generated continuously growing LCLs following infection of isolated PBLs with EBVcontaining
supernatants from UADT MPN patients and cancer free, healthy, control
individuals. Large scale population based studies requiring patient derived material
have also been conducted using isolated lymphocytes, short term lymphocyte cultures
or blood cultures 202-204 . However the major limitation of using isolated lymphocytes
and short term lymphocytes cultures is that multiple experiments cannot be conducted
on single sample due to limited sample availability. Also in such cases, repeated
collection of the starting material from individuals becomes unethical as well as
impractical, especially from patients who are lost to follow up or due to death of the
subject during an ongoing study. Therefore the generation of EBV cell lines is a
practical approach to tackle the limitation.
LCL have been regularly used as source of basic biomolecules like DNA,
including mitochondrial DNA, RNA and protein as well as for studies assessing DNA
damage/repair and apoptosis 57, 61, 62, 70, 73, 74, 205, 206 . However, there are a couple of
reports where the potential use of LCL as a surrogate of isolated lymphocytes has been
questioned and re-evaluated by comparing the results with freshly isolated or
cryopreserved lymphocytes 78-80, 207 . One of the reasons for occurrence of such variation
observed between LCL and isolated or cryopreserved lymphocytes could be the use of
136