Cytokeratin deposits in lymph nodes show distinct clinical significance from lymph node micrometastasis in human esophageal cancers.
BACKGROUND
Cytokeratin immunostaining is the most common method used to identify micrometastatic cancer cells from the lymph nodes. However, contamination with hyalinized cytokeratin particles, frequently observed in the lymph nodes of esophageal cancer patients, can lead to misinterpretation of cytokeratin immunostaining.


METHODS
Cytokeratin immunostaining (AE1/AE3) of surgically removed lymph nodes was performed for 41 cases of node-negative, but locally advanced (T3, T4), esophageal cancer patients. Cytokeratin immunoreactivity (CK) was classified as micrometastasis (MM) or cytokeratin deposit (CD) by the presence or absence of tumor nuclei in serial sections given hematoxylin-eosin staining.


RESULTS
CK (+) was observed in 18 patients (44%), including 11 with MM (+) (27%) and 10 with CD (+) (24%). There was no correlation between MM and CD, and neither was associated with clinicopathological factors, except for a high incidence of preoperative chemotherapy in CD (+) patients. The presence of CK did not affect postoperative survival of esophageal cancer patients at this limited stage, showing a 5-year survival rate of 57% for CK (+) and 64% for CK (-) (P = 0.6064). Interestingly, patients with MM (+) showed poorer prognosis than MM (-) (5-year survival: 28% vs 79%, P = 0.0188), while CD (+) patients tended to display better prognosis than CD (-) ones (5-year survival: 78% vs 56%, P = 0.1860).


CONCLUSIONS
Evaluation by cytokeratin immunostaining of lymph nodes requires careful discrimination of CD from MM, in order to allow MM to be used as a prognostic factor for esophageal cancer patients.
Doki
Yuichiro
Y
Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
Ishikawa
Osamu
O
Mano
Masayuki
M
Hiratsuka
Masahiro
M
Sasaki
Yo
Y
Kameyama
Masao
M
Ohigashi
Hiroaki
H
Murata
Kohei
K
Yamada
Terumasa
T
Miyashiro
Isao
I
Yokoyama
Shigekazu
S
Ishiguro
Shingo
S
Imaoka
Shingi
S
D004938:Esophageal Neoplasms / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism*; D008207:Lymphatic Metastasis / Q000473:pathology*; D011379:Prognosis
D007633:Keratins