Prognostic significance of CCND1 (cyclin D1) overexpression in primary resected non-small-cell lung cancer

Abstract

Summary Amplification of the CCDNI gene encoding cyclin DI was examined by Southern blotting and multiplex polymerase chain reaction (PCR) and occurred in 8 of 53 patients (15%) with primary resected nonsmall-cell lung cancer (NSCLC). These tumours and 17 additional tumours with a normal gene copy number showed overexpression of cyclin Dl (25/53, 47%), as assessed by immunostaining using a monoclonal antibody. In 22/25 cases, cyclin DI was localised in the cytoplasm, but some (7/25) had simultaneous nuclear staining. This result is in marked contrast to that reported in breast, hepatocellular and colorectal carcinoma studies where immunostaining was invariably nuclear. Examination of a restriction fragment length polymorphic (RFLP) site within the 3'untranslated region of the cDNA following reverse transcriptase (RT)-PCR (29/53 informative cases) showed a strong association between cytoplasmic staining and imbalance in allele-specific message levels. Cyclin Dl overexpression was associated with a poorly differentiated histology (P=0.04), less lymphocytic infiltration of the tumour (P=0.02) and a reduction in local relapse rate (P =0.01). The relative risk of local relapse was 9.1 in tumours without cyclin Dl overexpression (P = 0.01, Cox regression analysis). We conclude that genetic alteration of cyclin Dl is a key abnormality in lung carcinogenesis and may have diagnostic and prognostic importance in the treatment of resectable NSCLC.

Cyclin D1: polymorphism, aberrant splicing and cancer risk

“…By contrast, the A870 allele is predicted to hinder the splicing event, thus allowing for read-through into intron 4 and production of a variant splice product of cyclin D1, termed 'transcript b'. Consistent with this hypothesis, Betticher et al (1995), Holley et al (2001), and Howe and Lynas (2001) demonstrated that the A-allele of cyclin D1 was preferentially associated with transcript b production. However, individuals with the A/A genotype can still produce transcript a (Bala and Peltomaki, 2001;Holley et al, 2001), thus indicating that the 870-A allele is not completely penetrant for transcript b production, and individuals with the G/G genotype can produce transcript b.…”

“…Two transcripts of cyclin D1 can be detected in normal cells (Howe and Lynas, 2001), although regulation of splicing appears to be most relevant in cancer. Numerous groups have detected a cyclin D1 message that derives from alternative splicing (Betticher et al, 1995;Hosokawa et al, 1997Hosokawa et al, , 1999Bala and Peltomaki, 2001). This isoform was initially defined following the identification of the G/A870 polymorphism, that occurs at the intron 4/exon 5 boundary.…”

Alternative splicing of the human CDC25B tyrosine phosphatase. Possible implications for growth control?

“…Twò PISLRE', CDK-related proteins that are probable splice variants of the same gene have been cloned (Brambilla and Draetta, 1994;Grana et al, 1994) and a cyclin E splicing variant that lacks 49 amino-acids within the cyclin box and is therefore unable to bind cdk2 has been found in several cell lines (Sewing et al, 1994). Alternate splicing resulting in the production of a novel cyclin D1 transcript has also been identi®ed and appears to be modulated by A/G polymorphism located at the splice donor region of exon 4 (Betticher et al, 1995). However, this polymorphism is not speci®c for tumour cells, although it might be associated with higher risk of non-small cell lung cancer relapse.…”

Induced expression of human CCND1 alternative transcripts in mouse Cyl‐1 knockout fibroblasts highlights functional differences

“…It seems unlikely, therefore, that cytoplasmic staining observed using DCS-6 on paraffin sections from tumour cells is exclusively the protein product of CCND1 trb . 23,33,34 Interestingly constitutive expression of cyclin D1 TRB protein has been shown to be localized in the nucleus throughout the cell cycle and is associated with cellular transformation, in contrast cyclin D1 TRA is exported to the cytoplasm at the G 1 -S boundary and is a weak oncogene. 29,30 This may have a bearing on clinical outcome in some tumour types.…”

“…22 Further expression of cyclin D1 in tumours detected by immunohistochemical staining has been associated with patient prognosis in a number of cancers including, breast, squamous cell carcinoma of the head and neck (SCCHN), lung, pancreatic and bladder cancer. [23][24][25][26][27] Until recently, less consideration has been given to the function of the protein product from CCND1 trb . Sawa et al 28 have demonstrated that when overexpressed in human malignant glioma cells, the alternatively spliced forms of cyclin D1 modulate entry into the cell cycle in an inverse manner.…”