Question : perl regex replace

I read in a file in perl into a string using
my $file= do { local $/; <INFILE> };

the file contains the following and I need to replace what is in VarFNC("neednewdatahere").
How can I make a regex to do this?

function thisismyfunction()
  {
     myVar= new VarFNC("thisisthedata");
     myVar.startLog();

Answer : perl regex replace

Perhaps like this:

1:	$file =~ s/VarFNC\("[^"]+"\)/VarFNC("neednewdatahere")/g;