Cyclin D1 and retinoblastoma protein expression in oesophageal squamous cell carcinoma

To assess the immunoexpression of cyclin D1 and retinoblastoma in a cohort of oesophageal squamous cell carcinoma cases from South Africa to see whether there is a relation between these two proteins. In addition, protein expression was correlated with clinicopathological features.

Fifty biopsies and 30 oesophagectomy specimens were immunostained with commercially available antibodies to cyclin D1 and retinoblastoma proteins, following microwave antigen retrieval.

Twenty three of the 80 cases (29%) showed cyclin D1 protein expression. However, only five cases had > 50% of the tumour cells displaying immunopositivity. Three of the four cases with lymph node spread were cyclin D1 positive in the primary tumour and the metastasis. Fifty three cases were immunoreactive with the antiretinoblastoma antibody; 29 of these cases showing > 50% of cells with immunolabelling. Of the 23 cyclin D1 positive cases, 18 were also retinoblastoma positive. No correlation was observed between cyclin D1 and retinoblastoma protein expression and age, sex, race, or histological grade.

Cyclin D1 is expressed in a minority of cases of oesophageal squamous carcinomas from South Africa. However, three of four cases with lymph node spread were cyclin D1 positive, thus indicating that cyclin D1 positive tumours may have a greater propensity for spread. In addition, 18 of 23 cyclin D1 positive cases also expressed retinoblastoma protein. These findings suggest a possible relation between cyclin D1 and retinoblastoma proteins in a proportion of cases of oesophageal squamous.