TY - JOUR
T1 - Clear cell squamous cell carcinoma of the tongue exhibits characteristics as an undifferentiated squamous cell carcinoma
AU - Hasegawa, Kana
AU - Fujii, Shinsuke
AU - Kurppa, Kari J.
AU - Maehara, Takashi
AU - Oobu, Kazunari
AU - Nakamura, Seiji
AU - Kiyoshima, Tamotsu
N1 - Publisher Copyright:
© 2022 Elsevier GmbH
PY - 2022/7
Y1 - 2022/7
N2 - Clear cell squamous cell carcinoma (CCSCC), where cells show abundant clear cytoplasm, –is a variant of squamous cell carcinoma (SCC) and a rare entity in the oral cavity. The characteristics of CCSCC, especially in immunohistochemical features, remain unclear. We characterized a case of CCSCC arising from the oral mucosal epithelium of tongue, where the clear cell lesion accounted for a predominant portion of the tumor. This CCSCC, which was partially surrounded by conventional SCC, exhibited cellular atypia immunohistopathologically and histopathologically with a high Ki-67 index, increased number of mitotic figures and enlarged nuclei. Intravascular invasion of the carcinoma cells was also observed. Furthermore, the CCSCC recurred and metastasized to the cervical lymph nodes and both lungs three months after resection. Immunohistochemical analyses demonstrated decreased expression of p40 (an isoform of SCC marker p63), ADP-ribosylation factor (ARF)-like 4c (ARL4C), yes-associated protein (YAP) and 5-methylcytosine (5mC) in the CCSCC lesion compared with the surrounding SCC lesion, where the expression of ARL4C was upregulated compared with non-tumor region and YAP showed nuclear translocation. In addition, siRNA loss-of-function experiments revealed that p63 expression was required for ARL4C expression and DNA methylation was induced by p63 and YAP/transcriptional co-activator with PDZ-binding motif (TAZ) signaling in oral SCC cell lines. These results suggest that CCSCC, in which several markers of SCC-associated intracellular signaling pathways are downregulated, together with evidence of altered epigenetic regulation, is characterized as an undifferentiated SCC variant.
AB - Clear cell squamous cell carcinoma (CCSCC), where cells show abundant clear cytoplasm, –is a variant of squamous cell carcinoma (SCC) and a rare entity in the oral cavity. The characteristics of CCSCC, especially in immunohistochemical features, remain unclear. We characterized a case of CCSCC arising from the oral mucosal epithelium of tongue, where the clear cell lesion accounted for a predominant portion of the tumor. This CCSCC, which was partially surrounded by conventional SCC, exhibited cellular atypia immunohistopathologically and histopathologically with a high Ki-67 index, increased number of mitotic figures and enlarged nuclei. Intravascular invasion of the carcinoma cells was also observed. Furthermore, the CCSCC recurred and metastasized to the cervical lymph nodes and both lungs three months after resection. Immunohistochemical analyses demonstrated decreased expression of p40 (an isoform of SCC marker p63), ADP-ribosylation factor (ARF)-like 4c (ARL4C), yes-associated protein (YAP) and 5-methylcytosine (5mC) in the CCSCC lesion compared with the surrounding SCC lesion, where the expression of ARL4C was upregulated compared with non-tumor region and YAP showed nuclear translocation. In addition, siRNA loss-of-function experiments revealed that p63 expression was required for ARL4C expression and DNA methylation was induced by p63 and YAP/transcriptional co-activator with PDZ-binding motif (TAZ) signaling in oral SCC cell lines. These results suggest that CCSCC, in which several markers of SCC-associated intracellular signaling pathways are downregulated, together with evidence of altered epigenetic regulation, is characterized as an undifferentiated SCC variant.
KW - ARL4C
KW - Clear cell SCC
KW - OSCC
KW - P63
KW - Tongue
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U2 - 10.1016/j.prp.2022.153909
DO - 10.1016/j.prp.2022.153909
M3 - Article
C2 - 35552085
AN - SCOPUS:85129738787
SN - 0344-0338
VL - 235
JO - Pathology Research and Practice
JF - Pathology Research and Practice
M1 - 153909
ER -