Do you publish press releases on a section of your site? If so – you need to nofollow those links:

Throughout the video, John Mueller equated press releases to advertisements. It was specifically asked if all links in press releases need to be nofollowed or just “links with optimized anchor text” in press releases need to be nofollowed. While John said it would be somewhat okay to have direct URLs linked within press releases that are followed, he did say to be safe, he’d recommend nofollowing even those links (i.e. the links that are not even optimized anchor text).

Short version – make sure that links in any press release you’ve published directly are no followed – or you risk the ranking of your site.