<nowiki>*</nowiki>Level 1: present in WHO classification or professional practice guidelines; Level 2: recurrent in well-powered studies with suspected clinical significance; Level 3: recurrent, but uncertain prognostic significance. | <nowiki>*</nowiki>Level 1: present in WHO classification or professional practice guidelines; Level 2: recurrent in well-powered studies with suspected clinical significance; Level 3: recurrent, but uncertain prognostic significance. |