Aberrant expression of cyclin A and cyclin B1 proteins in oral carcinoma

Abstract

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in cell cycle. Aberrant exprssion of cylcin proteins has been found in a number of human cancers, including carcinomas of the head and neck, where amplification of the cyclin D1 gene is a common finding. The obective of this study was to examine cell cycle kinetics in oral carcinomas by determining the expression the S phase protein cylcin A and the M phase protein cyclin B1. Routinely processed tissue sections of 50 oral squamous cell carcinomas from the floor of the mouth were stained by immunohistochemistry for cyclin A, cyclin B1 and Ki‐67 proteins. Ten specimens of normal epithelium from the floor of the mouth were used as controls. Teh number of cells showing nuclear staining for cylin A, cyclin B1 and Ki‐67 proteins was determined by computer image analysis. There were 17 well‐differentiated, 25 moderately differentiated and 8 poorly differentiated tumours. Mean counts for cylcin A (29.50 ± 4.10, Mean ± 95% CI), cyclin B1 (2.05 ± 0.30) and Ki‐67 (49.46 ± 5.91) protiens in the carcinomas were significantly higher than counts for the normal epithelial controls (cyclin A: 930 ± 1.72; cyclin B1: 1.01 ± 0.36; Ki‐67: 17.4. ± 4.17). For cyclin A, cyclin B1 and Ki‐67, mean staining scores fosr all tumour grades were significantly higher than controsl. There was a strong correlation between ki‐67 and cyclin A scores in all tumour groups (r2=0.68); however, the correlations between cyclin B1 and Cyclin A Scores(r2=0.35) and between clylcin B1 and ki‐67 scores (r2=0.39) were weak. We conclude that there is overexpression of cyclin A and cyclin B1 proteins in oral carcinoma. Furthermore, the poor correlations for cylcin B1 scores with other cell cycle indices suggest that there may be aberrant cell cycle progression at G2/M checkpoint in oral carcinomas.

Identification of Biomarkers for Diagnosis of Gastric Cancer by Bioinformatics

“…The overexpression of CCNB1 can result in uncontrolled cell growth through cell cycle in cancer cells. High expression level of CCNB1 has been detected in variety of cancers, including breast cancer (Kawamoto et al, 1997), colorectal cancer (Wang et al, 1997), prostate cancer (Mashal et al, 1996) and oral cancer (Kushner et al, 1999), as well as GC (Yasuda et al, 2002). It corresponded with our result that CCNB1 was 3.92 FC in GC compared with normal control.…”

Inhibitory Effects of Oligostilbenoids from the Bark of <i>Shorea roxburghii</i> on Malignant Melanoma Cell Growth: Implications for Novel Topical Anticancer Candidates

“…Cyclin B is necessary for the G2/M phase transition during cell cycle progression. Overexpression of cyclin B1 has been reported in a variety of tumors, including breast, colon, prostate, oral, non-small cell lung cancers, and melanoma, [26][27][28][29] suggesting that dysregulation of cyclin B1 may contribute to the loss of normal cell cycle control during tumorigenesis. In particular, disruption in cyclin B1 expression resulted in the induction of cell cycle arrest followed by apoptotic cell death.…”

Oral squamous cell carcinoma versus oral verrucous carcinoma: an approach to cellular proliferation and negative relation to human papillomavirus (HPV)

“…However, few studies have investigated the relationship between the cellular proliferation index and the presence of HPV [24,25,30,31]. Huang et al [22] postulated that HPV may contribute to the carcinogenesis of oral epithelial cells and that it may function to stimulate both the transformation and proliferation of SCC.…”

“…In recent times, many investigations of cellular proliferation in neoplastic lesions have been undertaken and several different methods have been developed to detect it in malignancies [23][24][25][26][27][28][29][30][31][32][33]. However, few studies have investigated the relationship between the cellular proliferation index and the presence of HPV [24,25,30,31].…”