Case Report
Pleomorphic Carcinoma of the Lung Associated with Loss of Heterozygosity of p53 Gene
NORIMASA ARITA,1 YOSHIKI MIKAMI,2 MINAKO YOSHIDA,2 ICHIRO KONISHI,3 NORIO HORIIKE,3 KATSUTOSHI MIYAUCHI,4 TATSUHIKO MIYAZAKI,1 MASATO NOSE1 and MASAO ONO2
1Department of Pathology, 3The Third Department of Internal Medicine, 4The First Department of Surgery, Ehime University School of Medicine, Shigenobu, Ehime, and 2Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
We report a case with pleomorphic carcinoma of the lung in a 70-year-old man. Pleomorphic carcinoma is characterized by a heterogenous composition that includes epithelial and mesechymal malignancies. In the present case, the tumor was composed of a mixture of unequivocal squamous cell carcinoma and spindle cell components resembling sarcomatous overgrowth. The spindle component did not include a heterologous mesenchymal element characterized by overt differetiation for bone, cartilage, neuron or muscle tissue. To evaluate a state of differentiation of the spindle cell component, we immunohistochemically examined expression of the antigens including vimentin, cytokeratin, sarcomeric actin, α-smooth muscle actin, S-100 protein, CD34, Factor VIII, and CD68. The results showed sole expression of vimentin in the spindle cell component, suggesting an immature state of the mesenchymal lineage. Furthermore, the spindle cell component of this case was genetically characterized by loss of heterozygosity (LOH) at a codon 234 of exon 7 of the p53 gene. This mutation causes an amino-acid replacement (Tyr to Cys), which was previously proven to attenuate p53 function. The present case may suggest a relation between somatic alteration of the p53 gene and histogenesis of pleomorphic carcinoma.
keywords —— Pleomorphic; carcinoma; p53 gene; loss of heterozygosity
© 2005 Tohoku University Medical Press
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Tohoku J. Exp. Med., 2005, 206, 181-185
Correspondence: Dr. Masao Ono, M.D., Department of Pathology, Tohoku University Graduate School of Medicine, 2-1, Seiryo, Aoba, Sendai, Miyagi 980-8575, Japan.
e-mail: onomasao@mail.tains.tohoku.ac.jp