DNA index, cellular proliferative activity and nucleolar organizer regions in cancers of the larynx

Abstract

The DNA index, expression of cell-cycle-related proteins--proliferating cell nuclear antigen (PCNA, cyclin) and Ki-67--and the content of silver-binding nucleolar organizer regions (AgNORs) were evaluated in 30 unselected consecutive primary squamous cell carcinomas of the larynx. Results were compared and subsequently related to histological grading, lymph node status, pT category, and pathological stage. DNA content was non-diploid in 9 cases (30%). Mean AgNOR counts per tumor ranged from 2.52 to 8.76. PCNA and Ki-67 expressions were similar in 10 cases (33%). In the remaining cases, PCNA-positive cells usually outnumbered Ki-67-positive cells. No significant correlation was found among DNA index, PCNA and Ki-67 expressions, and AgNOR counts. Although there was a positive trend when Ki-67 was compared with histological grading, findings were not statistically significant. In contrast, a significant correlation was found between DNA index and lymph node status (P = 0.035), with a higher incidence of neck node metastases in non-diploid tumors. These data suggest that tumor ploidy can be correlated with lymph node spread in laryngeal squamous cell carcinoma and might be used as an additional prognostic factor when planning treatment.