Briefly, by using the intense dark brown staining pattern (indicating late G1‐S-phase) and the PCNA-negative mitotic figures as definitive “signposts” in a spherical cycling clone (i.e., the cyst), it was determined that the protracted passage through the four phases of the cell cycle manifested as variations in the immunoexpression of PCNA in the different clone members. Here, PCNA is linked to cyst.