However, several parameters distinguish MGC from BCC samples: (i) the mRNA level of the shelterin subunits decreased in MGC but it increased in BCC; (ii) P53 was more highly mutated in MGC; (iii) Siah1 mRNA was over-expressed in BCC; (iv) BCC samples contain a higher level of senescent cells; (v) Ki-67 and Bcl2 expression were lower in BCC.
As cFlip and Bcl-2 are highly expressed in BCCs, as a consequence of high Gli2 expression, this may explain the marked resistance of the tumor to the extrinsic and intrinsic apoptotic pathway.
Expression of Bcl-2, Bax, and Ki-67 was immunohistochemically investigated in both normal skin and BCC cells, as well as in the epidermis overlying BCC.
An increased expression of stromal alpha-smooth muscle actin with a concomitant decrease or loss of bcl-2 expression may be highly suggestive of aggressiveness in basal cell carcinoma.
This spontaneous apoptosis decreases with increasing bcl-2 (in basal cell carcinoma), whereas it does not appear to be related to p53 level expression.