G. Chausovsky et al., Expression of cytokeratin 20 in the blood of patients with disseminated carcinoma of the pancreas, colon, stomach, and lung, CANCER, 86(11), 1999, pp. 2398-2405
BACKGROUND. Cytokeratins are constituents of the intermediate filaments of
epithelial cells that are expressed in various combinations depending on th
e epithelial type and the degree of differentiation. The recently identifie
d cytokeratin 20 (CK-20) was found to be expressed in colonic, gastric, and
pancreatic carcinoma tumor tissues. A low rate of incidence of expression
of CK-20 was found in tumor tissue from lung carcinoma but no expression wa
s found in blood even with the sensitive reverse transcriptase-polymerase c
hain reaction (RT-PCR) method. The objective of the current study was to ex
amine whether CK-20 expression in the blood can be used as a biomarker for
the detection of dissemination in patients with carcinoma of the colon, sto
mach, and pancreas.
METHODS, In the current study, RT-PCR was used to determine the expression
of CK-20 in the blood cells from patients with metastatic colon carcinoma (
n = 22), metastatic pancreatic carcinoma (n = 28), metastatic gastric carci
noma (n = 18), metastatic lung carcinoma (n = 13), no metastatic colon carc
inoma (n = 13) and no known malignant diseases (n = 22). RNA was extracted
from cell pellets and analyzed by RT-PCR using primers for CK-20.
RESULTS, In the group of 22 patients with metastatic colon carcinoma, 14 we
re found to be CK-20 positive (sensitivity of 63.6% and specificity of 92.3
%), 22 of the 28 pancreatic carcinoma patients showed positive CK-20 expres
sion, and 12 of 18 patients with gastric carcinoma showed positive CK-20 ex
pression. All patients with metastatic lung carcinoma except I were negativ
e (12 of 13 patients), and 12 of 13 patients with colonic carcinoma with no
known metastases also were negative. Negative CK-20 results were obtained
in all 22 patients with no known malignant diseases.
CONCLUSIONS. The results of the current study indicate that because of its
high sensitivity, RT-PCR of CK-20 is a potential biomarker for detecting me
tastases in blood samples from patients with carcinoma of the colon, stomac
h, and pancreas. (C) 1999 American Cancer Society.