During the permeabilization step, selecting the appropriate buffer it's crucial, as it can significantly impact the staining results and, consequently, the interpretation of your results. Methanol is often selected for its efficiency and simplicity. However, when staining with antibodies for transcription factors and some nuclear proteins, the Foxp3 Transcription Factor Staining Buffer Set (eBioscienceTM#00-5523-00) is recommended.