Immunohistochemical expressions of cytokeratins, mucin core proteins, p53, and neuroendocrine cell markers in epithelial neoplasm of appendix.
Epithelial neoplasms of appendix are infrequent, and their pathological features are not fully characterized. We collected 33 cases of appendiceal tumors and examined immunohistochemically the expression of cytokeratins (CK, CK7, and CK20), mucin core protein (MUC1, MUC2, MUC5AC, and MUC6), E-cadherin, chromogranin A, and p53 protein. Gene analysis of TP53 was also conducted on exons 5 to 8. Clinically, mucinous tumors were predominant in females. Immunohistochemically, all the tumors expressed CK20, whereas CK7 was positive in one third of the cases. Similarly, MUC2 was expressed in all the tumors, whereas MUC1 and MUC5AC were detected in about a half of the cases. Although chromogranin A-positive cells are generally sparse in normal appendix, they were more common in mucinous tumors than in nonmucinous tumors. Contrary to the previous data reported (Mod Pathol 2002;15:599-605), mucinous carcinoma exhibited a higher frequency of p53-positive cells (mean 29%) compared with mucinous adenoma (2.8%) (P < .001), whereas nonmucinous tumors showed high levels of p53-positive cells to similar extent (51%-67%) in both adenoma and carcinoma. The high expression of p53 protein coincided with the presence of mutations in multiple sites of TP53 gene in mucinous tumors. This is the first report that characterized the immunophenotypic profile of appendiceal epithelial neoplasms with an emphasis of a higher frequency of p53 positivity in mucinous carcinoma cases compared with mucinous adenoma in the appendix.
Yajima
Nobuhisa
N
Department of Pathology (I), Hirosaki University School of Medicine, Hirosaki 036-8562, Japan.
Wada
Ryuichi
R
Yamagishi
Shin-Ichiro
S
Mizukami
Hiroki
H
Itabashi
Chieko
C
Yagihashi
Soroku
S
D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000378:metabolism*; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000032:analysis*; D015820:Cadherins / Q000096:biosynthesis; D053379:Chromogranin A; D002864:Chromogranins / Q000096:biosynthesis; D004252:DNA Mutational Analysis; D005260:Female; D049669:History, 16th Century; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007633:Keratins / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009077:Mucins / Q000096:biosynthesis*; D009375:Neoplasms, Glandular and Epithelial / Q000378:metabolism*; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics
D014408:Biomarkers, Tumor; D015820:Cadherins; D053379:Chromogranin A; D002864:Chromogranins; D009077:Mucins; D016159:Tumor Suppressor Protein p53; D007633:Keratins