[Histonet] TUNEL, formalin DNA breaks, CLCas3

[mesruh turkekul]

Dear All,

When I do TUNEL on FFPE mouse or human tumors I always run TUNEL and
ClCas3 on FFPE mouse embryos 12.5 days and mouse testis. Since I know
exactly where the apoptotic cells are in the embryos and testis  I see
no difference between TUNEL and ClCas3. In some cases some tumors are
positive with TUNEL but not positive with ClCas3 which means that
TUNEL maybe also staining necrotic cells which can be identified by
their morphology or it may indicate that there are some apoptotic
pathways which does not involve activation of ClCas3 but eventfully
form DNA breaks detected by TUNEL.
If in one paper it is mentioned that formalin creates DNA breaks it
does not mean it is true, on the contrary if there is only one paper
and nobody reproduced this result after 6 years I will remain
sceptical. I always trust papers and I always check their claims by
controls.

Regards,
Mesruh Turkekul
MSKCC MCCF
www.mskcc.org
New York, NY 10021