In this paper, we introduce an exact algorithm with a time complexity of $O^*(1.325^m)$ for the {\sc weighted mutually exclusive maximum set cover} problem, where $m$ is the number of subsets in the problem. This is an NP-hard motivated and abstracted from a bioinformatics problem of identifying signaling pathways based gene mutations. Currently, this problem is addressed using heuristic algorithms, which cannot guarantee the performance of the solution. By providing a relatively efficient exact algorithm, our approach will like increase the capability of finding better solutions in the application of cancer research.