As suggested, we analyzed the distribution of IRS (immunoreactivity score) across the cohort. In Figure 1 it can be clearly seen that there are two groups forming here, those with 0-4 and those with 6-12 IRS. In addition, we calculated the survival probability depending on the IRS (Figure 2). Patients with an IRS of 6 or higher have a similar bad prognosis compared to patients with an IRS below 5. A better survival correlates with lower MACC1 IRS. Patients with an IRS of 0 have the best prognosis. Based on these two analyses, the decision for cut-off value of 5 was made. Additionally, ROC curve analysis showed, that the IRS value of 5 has the highest Youden Index and is therefore the most suitable cut-off value. 0.408) (Figure 3 and Table 1). Looking at MACC1 expression in cell lines and tissue samples, the variability looks similar. Nevertheless, it must be considered that the investigation of the homogeneous cell lines is a purely quantitative analysis of the expression by Western plot and RT-PCR. The analysis of the tissue samples by immunoreactivity score analyses both the strength of expression and the inhomogeneity of expression. Figure 1: Distribution of the IRS across the cohort Figure 2: Overall Survival depending on the IRS Figure 3: ROC Curve for IRS cut-off analysis (AUC 0.716 [0.656 – 0.776]) Table 1: Sensitivity, specificity and Youden Index for different IRS cut-off values.
The results are interesting and may have clinical relevance.