Fig. 5From: Pathologically confirmed spontaneous regression of small cell lung cancer after computed tomography-guided percutaneous transthoracic needle biopsy followed by surgeryImmunohistochemical staining of the resected specimens. CD4-positive (A) and CD-8 positive (B) T-lymphocytes were observed around the tumor. The immunohistochemical staining of the tumor could not be conducted due to its extremely small sizeBack to article page