Microphone leakage occurs in multichannel close-talk audio recordings of a meeting, when speech of an active speaker couples into both the dedicated target microphone and all other microphone channels. For an automatic transcription or analysis of a meeting, the interferer signals in the target microphone channels have to be eliminated. Therefore, we apply a frequency domain adaptive filtering-based multichannel acoustic echo cancellation (MAEC) method, which typically requires clean reference channels. We consider a wide range of different speech-to-interferer ratios and evaluate two cascading schemes for the MAEC, which leads to an improved speech component quality and interferer reduction by up to 0.1MOS points and 0.5dB, respectively. However, the purpose of this work is not to improve the MAEC method, but instead to show that it can be successfully applied to microphone leakage reduction, such as in meetings with headset-equipped participants. Therefore, we analyze and point out why the MAEC method is able to cancel the interferer signals in this scenario even though the reference signals are themselves disturbed by interfering speech portions.