CALB2 and sarcomatoid mesothelioma: Bcl-2 protein shows intense cytoplasmic positivity but has to be differentiated from bcl-2 positive lymphomas.[8] Thirty percent of synovial sarcomas show S100 protein positivity but one has to keep in mind malignant peripheral nerve sheath tumor in ruling out as a possibility.[10] Sarcomatoid mesothelioma can be excluded by doing calretinin and HBME1.