In recent years, immunohistochemistry as applied to the Bcl-2 family of proteins has represented a burgeoning area of interest to cancer researchers. The majority of studies have focused on the original member Bcl-2, first identified via its involvement in the common t(14;18) chromosomal translocation in B-cell lymphomas (
1 ). However, since this discovery, preclinical and clinical interest in Bcl-2 has dramatically increased owing to (a) its recognition as the first of a new class of oncogene able to prolong survival by inhibiting programmed cell death (apoptosis) and (b) the discovery of many additional related genes/proteins some of which, like Bcl-2, inhibit apoptosis, whereas others, such as Bax, conversely promote cell death (
2 ) (Table 1 ).
Table 1 Bcl-2 Family Members
Pro-apoptotic
|
Anti-apoptotic
|
Bax
|
Bcl-2
|
Bcl-Xs
|
Bcl-Xl
|
Bak
|
Bcl-w
|
Bad
|
Bfl-1
|
Bid
|
Brag-1
|
Bik
|
Mcl-1
|
Hrk
|
A1
|