A significant amount of research has gone into trying to elicit the clinical/pathological and/or chromosomal/molecular features of primary uveal melanomas that are predictive of developing metastatic disease. Clinical/pathological features that are associated with increased risk of metastatic disease include increased patient age, increased tumor diameter and thickness, involvement of the ciliary body, epithelioid cytology, extraocular extension, extravascular matrix patterns, and lymphocytic/monocytic inﬁltration into the tumor. However, no one of these features is as strongly predictive as particular chromosomal/molecular features.
Every normal cell has 22 pairs of chromosomes (i.e., two chromosome 1s, two chromosome 2s, etc.) and 2 sex chromosomes (XX = female or XY = male). In order to understand the nomenclature of chromosomal aberrations one must understand that each chromosome is structured such it contains a “short arm” referred to as ‘p’ and a “long arm” referred to as ‘q’ that emanate from a central point called the centromere. Primary uveal melanoma tumors tend to have very defined chromosomal alterations. Each tumor can have one of a number of chromosomal alterations: loss of p on chromosome 1, loss of an entire chromosome 3 (monosomy 3), gain of p on chromosome 6, loss of q on chromosome 6, loss of p on chromosome 8, and gain of q on chromosome 8. A tremendous amount of work has gone into trying to associate these chromosomal alterations with prognosis of metastatic disease. Among these chromosomal aberrations, the most powerful predictor of future metastatic disease is clearly the identification of monosomy 3 in a primary uveal melanoma tumor. The presence of 6p gain is nearly always mutually exclusive with monosomy 3 and predictive of not developing metastatic disease.
For the role of Gene Expression Analysis in predicting future metastatic disease seehttp://talkabouthealth.com/what-are-gene-expression-patterns-and-how-are-they-used-to-help-predict-prognosis-for-uveal-melanoma
Currently, the most predictive, and thus employed factors, for assessing an individual patient’s risk of developing metastatic disease is monosomy 3 status (the presence of monosomy 3 being a poor prognostic factor) or gene expression profile (class 2 status being a poor prognostic factor).