Author/Editor		Coer, Andrej; Pižem, Jože; Gale, Nina
Title		The expression of Bcl-2 and pro-caspase 3 in head and neck squamous cell carcinoma
Translated title		Izražanje Bcl-2 in prokaspaze 3 v ploščatoceličnih karcinomih glave in vratu
Type		članek
Source		Zdrav Vestn
Vol. and No.		Letnik 71, št. Suppl 3
Publication year		2002
Volume		str. III-39-43
Language		eng
Abstract		Background. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer and accounts for 6% of cancers worldwide. A better understanding of its biology could lead to improved treatment options. Generally, the goal of cancer treatment is to abolish cell proliferation and to induce necrotic or aptoptotic cell death. Apoptosis has been recognized as a key mechanism of tumour cell elimination. Different apoptotic signals converge to induce caspase cascade activation. Caspase 3 is the central executioner caspase and is necessary for effective apoptotic cell death. Bcl-2 protein family regulates apoptosis. The Bcl-2 protein itself is a product of a proto-oncogene and has an antiapoptotic action. Methods. In our study, the expression of Bcl-2 and pro-caspase 3 by immunohistochemistry in 28 HNSCC graded into well, moderately and poorly differentiated cancers were investigated. Results. Our results of Bcl-2 expression confirm and extend previous reports in which Bcl-2 over-expression has been recognised as an important parameter in HNSCC biological behaviour. Three of 28 tumours (11%) showed significant Bcl-2 expression. Two of them were poorly and one was moderately differentiated. Pro-caspase 3 immunoreactivity was confined mainly to the cytoplasm. Absent or low pro-caspase 3 immunoreactivity was found only in 1 of 6 well differentiated and in 1 of 10 moderately differentiated tumours in contrast to 5 of 12 poorly differentiated tumours. In six of 12 poorly differentiated tumours procasapse 3 immunoreactivity was strongly positive. In two cases hyperplastic epithelium was strongly positive in contrast to adjacent HNSCC in the same slide which was completely negative for pro-caspase 3. Conclusions. Our results indicate downregulation of pro-caspase 3 expression, especially in poorly differentiated HNSCC. Further studies are needed to test whether this is related to HNSCC behaviour and predict treatment outcome.
Summary		Izhodišča. Ploščatocelični karcinom glave in vratu (HNSCC) je šesti najpogostejši tumor in predstavlja 6% vseh malignomov pri ljudeh. Natančnejše razumevanje molekularnih mehanizmov nastanka teh karcinomov bi omogočilo njihovo učinkovito zdravljenje. Cilj zdravljenja tumorjev je ustaviti delitve tumorskih celic ali povzročati njihovo smrt bodisi z apoptozo ali nekrozo. Vse več raziskav kaže na to, da je apoptoza pomemben način smrti tumorskih celic. Različni proapoptotični signali, ki delujejo na celice, sprožijo kaskadno aktivacijo kaspaz. Efektorske kaspaze, kot je kaspaza 3, potem dokončajo proces apoptoze. Družina genov bcl-2 predstavljajo geni, ki nadzorujejo proces apoptoze. Eden od članov te družine, protoonkogen bcl-2 kodira beljakovino, ki zavira apoptotsko aktivnost v celicah. Metode. V naši raziskavi smo imunohistokemično analizirali izražanje Bcl-2 in prokaspaze 3 v 28 HNSCC, ki smo jih glede na gradus razdelili v dobro, zmerno in slabo diferencirane karcinome. Rezultati. Naši rezultati izražanja Bcl-2 v analiziranih tumorjih so dopolnili že objavljene raziskave, ki kažejo, da prekomerno izražanje Bcl-2 pomembno vpliva na biološko obnašanje HNSCC. Trije od 28 tumorjev (11%) so bili Bcl-2 pozitivni, od tega dva slabo diferencirana in en zmerno diferenciran HNSCC. Izražanje prokaspaze 3 se je imunohistokemično kazalo v citoplazmi. Nizko izražanje ali celo neizražanje prokaspaze 3 je bilo vidno v enem od šestih dobro diferenciranih in enem od desetih zmerno diferenciranem HNSCC, nasprotno pa kar v petih od dvanajstih slabo diferenciranih karcinomih. V šestih slabo diferenciranih karcinomih od dvanajstih pa je bilo izražanje prokaspaze 3 močno pozitivno. V dveh primerih je bilo izražanje prokaspaze 3 v hiperplastičnem epiteliju ob karcinomu močno pozitivno, nasprotno pa je bil karcinom v istem preparatu povsem negativen. (Izvleček prekinjen pri 2000 znakih).
Descriptors		HEAD AND NECK NEOPLASMS CARCINOMA, SQUAMOUS CELL GENES, BCL-2 IMMUNOHISTOCHEMISTRY