Researchers discover tumour suppressor promotes cancer
actually stimulate tumour progression, which if confirmed, could
raise possibilities of using the gene as a novel prognostic
indicator of tumour aggressiveness.
The gene, H-REV107-1 is thought to stimulate tumour progression in some non-small cell lung carcinomas. Lung cancer is responsible for more deaths than any other cancer, with only 15 per cent of patients reaching 5-year survival, and non-small cell lung cancer accounting for 75 per cent of all lung cancer.
The researchers found H-REV107-1 expression in a portion of human non-small cell lung carcinomas (NSCLC), samples examined.
When they further characterised this expression in relation to normal lung tissue, H-REV107-1 was found in nonproliferating and proliferating cells in normal lung tissue, localised mainly to the nucleus.
In cultured NSCLC cells, however, H-REV107-1 was found in either the cytoplasm or both the cytoplasm and nucleus.
The group then examined whether cellular localisation of H-REV107-1 in NSCLC tumour samples is linked with tumour behaviour.
They found that cytoplasmic localisation correlated with decreased patient survival (24 months versus 41 months for nuclear localisation).
This data suggested that cytoplasmic H-REV107-1 stimulates cell growth and was later confirmed by suppression of H-REV107-1 RNA, which inhibited cell proliferation, and overexpression of H-REV107-1 protein, which stimulated cell growth pathways and increased proliferation.
The data demonstrated that H-REV107-1 exerts pro-growth functions within a subset of NSCLC cells in a location-dependent manner.
Similar reverse functions have been identified for other tumour suppressors, but the correlation between H-REV107-1 expression and NSCLC patient survival is quite striking.
The related report is by Nazarenko et al and is titled: "H-REV107-1 stimulates growth in non-small cell lung carcinomas via the activation of mitogenic signalling." It appears in the October issue of The American Journal of Pathology.
