Expression of the metastasis suppressor gene KISS1 in uveal melanoma.

PURPOSE

Uveal melanoma (UM) is the most common primary malignant intraocular tumour in adults. Forty-five percent of UM patients develop metastasis within 15 years of initial diagnosis. KISS1, a human metastasis suppressor gene, has been reported to play a role in various human malignancies. The purpose of this study was to investigate the expression of KISS1 in UM and its potential value as a prognostic marker.

METHODS

Thirty-seven cases of paraffin-embedded human UM specimens were immunostained with a KISS1 antibody. Clinical-pathological data were obtained. The relationship between the clinical-pathological data and the expression of KISS1 was evaluated. Moreover, the survival rates of the patients were also assessed. Five UM cell lines (92.1, OCM-1, MKTBR, UW1 and SP6.5) were assayed for KISS1 expression. In addition, real-time PCR was used to determine mRNA levels of KISS1and its receptor GPR54in these cell lines.

RESULTS

The immunohistochemical results of KISS1 expression displayed cytoplasmic staining in 84% of UM specimens. Low KISS1 expression was associated with a higher risk of metastatic disease (P<0.05). Furthermore, we found that KISS1 was expressed in all five UM cells lines. Real-time PCR analysis confirmed the presence of both KISS1and its receptor GPR54in all five human UM cell lines.

CONCLUSIONS

To the best of our knowledge, this is the first time that KISS1has been characterized in UM. The correlation between KISS1 expression and UM survival rate suggests an important role for KISS1as a prognostic marker in this particular tumour.