I understand ( tho I may be corrected and informed further), that PCNA is not the best marker to use, if you are assessing cells in cycle. It was, before Ki67 and H3? --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.690 / Virus Database: 451 - Release Date: 22/05/2004