Colon cancer is the third leading cause of death worldwide and sixth in India, 
where it is the cause of 5.8% of the total deaths. Pumilio-1 (PUM1) is an RNA 
binding protein whose regulatory role is by binding to the consensus 
5'UGUANAUA3' sequence on the 3'UTR of the mRNA targets and 
post-transcriptionally repressing their expression. This study is the first of 
its kind to report the expression or function of PUM1 in colon cancer. We found 
that PUM1 mRNA expression is high in primary and metastatic colon cancer cell 
lines when compared to the normal colon cell line. Immunohistochemistry analysis 
showed similar trend wherein compared to the normal colon tissue, PUM1 was found 
to be overexpressed in both adenocarcinoma and in metastatic carcinoma. This 
confirms the role of PUM1 in colon cancer progression. PUM1 overexpression study 
in HCT116 revealed that cells transfected with PUM1 plasmid show an increased 
rate of proliferation, migration and colony formation. Overexpressing PUM1 
increases the number and size of spheroids indicating the role of PUM1 in 
maintaining cancer stem cells. Overall, this is the first study that has shown 
the role of PUM1 in colon cancer development.