Transcript Diapositiva 1 - Siapec

IMMUNOHISTOCHEMICAL
EXPRESSION OF MELK IN BREAST
CANCER
Manieli C*, Saccani S*, Lai ML*, Pilloni L*, Coni PP*, Senes
G*, Faa G*, Van den Oord JJ°.
*I Cattedra Anatomia Patologica, University of Cagliari, Italy.
°University Hospitals, Katholieke Universiteit Leuven,
Belgium.
Background (1)
• MELK (Maternal Embryonic Leucine Zipper Kinase)
is a member of the snf1/AMPK family of serinethreonine kinases;
• Its specific targets in normal cells have not been
identified yet, and its role is therefore still elusive.
• However, several studies reported an increased
expression of MELK in various tumours compared to
normal tissues.
Background (2)
In breast cancer cell lines and in breast tumours an
elevated expression of MELK was found by semiquantitative RT-PCR and by Western Blot analysis;
MELK, by interaction with and phosphorylation of
Bcl-G, a pro-apoptotic member of the Bcl-2 family,
has an anti-apoptotic effect on tumour cells growth
in vitro. Meng-Lay Lin et al, Breast Cancer Research 2007,9:R17.
The aim of the present study was to
assess the expression of MELK by
immunohistochemistry, comparing
normal mammary tissue and breast
tumours.
Design
Immunohistochemical studies were performed on
frozen sections from 17 consecutive cases of breast
cancer and 4 cases of normal mammary gland, using
a mouse monoclonal antibody against Melk.
Immunostaining was also performed for Estrogen
(ER) and Progesteron (PR) Receptors and Cerb-B2.
Results (1)
Normal mammary gland
Invasive ductal carcinoma (IDC).
• MELK was not expressed in normal mammary gland
• 7 out of 17 breast tumours examined showed
immunoreactivity for MELK.
Results (2)
Invasive ductal carcinoma (IDC).
• A cytoplasmatic staining was present in all 7 cases; 5
cases showed both cytoplasmatic and nuclear stain.
• All Melk positive tumours were ER and PR positive and
Cerb-B2 negative.
Conclusions
Our data show that MELK is expressed by cancer cells in
a subgroup of breast tumours.
In addition, MELK expression was associated with
estrogen and progesteron receptor immunoreactivity.
The issue of whether MELK immunostaining may have a
prognostic significance in breast cancer needs further
studies.