$re = '/\b([A-Za-z]+\s*\([A-Z]+\)|[A-Z]+)(\s*-\d+[A-Z]+(?:,*\s*-\d+[A-Z]*)*|\s*-\d+(?:,*\s*-\d+)*)(?:,*\s*and\s+(-\d+))?/m';
$str = 'The Proteinase-Activated Receptor-2 interskin (IS)-1ALPHA, -8, -97, -2ALPHA, and -3 was specific antagonist. The LL-37, -15, SAC-1, -7, and -21 in keratinocytes was good.';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php