How to grep over a variable

I have a scenario like

VAR = `Some command brings the file path name and assigns it to VAR`

For example VAR can have value like /root/user/samp.txt

I want to grep command like

grep HI $VAR 

This doesnt works gives an error saying cannot open /root/user/samp.txt same error when tried cat $VAR.

How to handle this ?

I have given try

echo $VAR | grep HI
grep HI "$VAR"

Using korn shell