Prognostic indicators are characteristics that researchers have found that are good indications of what a patients prognosis might be. For instance, in one study, factors predictive of poorer survival among 337 patients with mesothelioma in Cancer and Leukemia Group B studies included: poor performance status, chest pain, dyspnea (difficulty breathing), platelet (platelets are found in the blood and help stop bleeding) count greater than 400,000/µL, weight loss, serum lactate dehydrogenase level greater than 500 IU/L, pleural involvement, low hemoglobin (carries oxygen in red blood cells) level, high white blood cell count, and age older than 75 years.
Molecular indicators of prognosis have been studied by other groups. Using the 12,000 U95 Affymetrix gene chip, one study developed a four-gene expression ratio test that was able to predict treatment-related patient outcome in mesothelioma independent of the histologic subtype (cell type) of the tumor. Using similar technology, another study reported a 27-gene expression array for mesothelioma prognosis. The gene classifier study showed the actual time to progression and survival of the test set with over 95% accuracy.
Clinical outcomes were independent of histology (cell type), and hereorgeneity of progression and survival in early-stage patients was well defined. These studies imply that gene expression data in mesothelioma at the time of the initial biopsy may accurately predict clinical outcome. Further validation in larger studies is required however to be sure of this.