melanin bleach query

From:Debbie Pepperal <>

Hi histonetters

One of our pathologists needs a melanin bleach performed on sections of
lymph node requiring IHC (S-100 and HMB45). From previous knowledge, I
recollect that if done prior to the IHC stain, the tissue washes off,
however, by doing it post IHC, would the chromagen (DAB) still be intact?
Will there be any fading of positive staining due to this procedure.
The lab does not have the reagents to do an APAAP test either, which
probably would help to  distinguish between the melanin pigment and the
true melanocytes.
All suggestions welcome.


Zenobia Haffajee
Newcastle, Australia

Zenobia Haffajee
Research Assistant
Anatomical Pathology 
HAPS John Hunter Hospital
Tel :(02) 4921 4449
Fax :(02) 4921 4507

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