Immunohistochemical analysis of pro- and active-caspase 3 in laryngeal squamous cell carcinoma.
Active caspase 3 is considered to be the main executioner caspase in apoptotic process. The mechanisms of apoptosis in laryngeal squamous cell carcinoma (LSCC) have been investigated by examining the expression profiles of pro-caspase 3 and active-caspase 3. The correlation between the two forms of caspase 3 and the p53 status was also determined. LSCCs ( n=65) were studied using immunohistochemistry with antibodies to pro-caspase 3, active-caspase 3 and p53. The expression of pro-caspase 3 was absent or weak in 16 (24.6%), moderate in 21 (32.3%) and strong in 28 (43.1%) cases. Survival curves for different levels of pro-caspase 3 differed, but the differences were not statistically significant. An apoptotic index (AI) was determined by quantifying the active-caspase 3-positive cells. The AI ranged from 0.2% to 9.4% and did not differ among the different levels of pro-caspase 3 expression. Even in cases in which the expression of pro-caspase 3 was considered negative, caspase 3-positive apoptotic cells were found. The AIs were significantly higher in supraglottic tumours compared with glottic counterparts ( P=0.008) and were higher in poorly differentiated tumours compared with well-differentiated and moderately differentiated LSCC ( P=0.06). No correlation between AI and p53 expression was found, although pro-caspase 3 expression trended to be higher in the p53-positive group of LSCC. Our results suggest that the expression of pro-caspase 3, a key executioner caspase in apoptosis, is downregulated in a proportion of LSCC, but this is not associated with decreased apoptotic activity, measured by active-caspase 3 labelling.
Cör
Andrej
A
Institute for Histology and Embryology, Medical Faculty of Ljubljana, Korytkova 2, 1000, Ljubljana, Slovenia, andrej.coer@mf.uni-lj.si
Pizem
Joze
J
Gale
Nina
N
D000328:Adult; D000368:Aged; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000401:mortality / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002452:Cell Count; D004792:Enzyme Precursors / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000201:enzymology* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D014408:Biomarkers, Tumor; D004792:Enzyme Precursors; D016159:Tumor Suppressor Protein p53; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases