# scenario 1:
$data = <<EOT1;
ignore this part

===Comments===

ignore this part too

===Comments===

capture this part

=Microarray Data=
EOT1

$match = ( $data =~ /.*===Comments===(.*?)=Microarray Data=/s )[0];
print $match;

# scenario 2:
$data = <<EOT2;
ignore this part

===Comments===

ignore this also

=Microarray Data=

and ignore this

===Comments===

this is what we want

=Microarray Data=
EOT2

$match = ( $data =~ /===Comments===(.*?)=Microarray Data=/sg )[1];
print $match;