Appending $_SERVER['QUERY_STRING'] safe?

[phpzone]

I just wanted to check, is appending QUERY_STRING to create $more_link like this considered ok or do people recommending sanitizing the variable in some way first?

 

<?php
  		foreach( $el->entries as $key=>$entry )
	  		{			

		$more_link = $_SERVER['PHP_SELF'] . '?' . $_SERVER['QUERY_STRING'] . '&entry_id=' . $entry['entry_id'];

  			print <<<_DISPLAY_ITEM

		<div class="blog-entry">

			<p class="blog-title">{$entry['entry_title']}</p>

			<p class="blog-preface">{$entry['entry_preface']}</p>

			<p class="blog-more"><a href="{$more_link}">read more</a></p>					

		</div>

_DISPLAY_ITEM;
?>