Apoptosis and its correlation with proliferative activity in rectal cancer.
OBJECTIVE
Alterations in the normal control of apoptosis and cell proliferation are important factors in multistep colorectal carcinogenesis. The aim of this study was to determine the frequency of apoptosis and cell proliferation in rectal cancers and to examine their relationship to clinicopathological variables and expression of bcl-2 and p53.


METHODS
Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining and immunohistochemical staining for Ki-67, bcl-2, and p53 were performed on paraffin-embedded tissue samples of 57 rectal cancers.


RESULTS
There was a positive linear correlation between apoptotic index (AI) and proliferative index (PI) (gamma = 0.276, P = 0.038). Both apoptosis and cell proliferation were more frequently found in rectal cancers with lymph node metastasis (P = 0.045 and 0.010, respectively). However, the ratio of AI and PI was not different by nodal status. There was no association between Dukes stage and AI or PI. The frequency of apoptosis was inversely related to the expression of bcl-2, but was not related to the p53 status of rectal cancer. There were no association between cell proliferation and the expression of bcl-2 or p53.


CONCLUSIONS
Our results suggest that the susceptibility to apoptosis in rectal cancer is clearly related to the proliferative activity and high turnover rate of tumor cells may contribute to lymph node metastasis.
Kim
Young-Ho
YH
Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Lee
Jun Haeng
JH
Chun
Hokyung
H
Nam
Seok-Jin
SJ
Lee
Woo-Yong
WY
Song
Sang Yong
SY
Kwon
O Jun
OJ
Hyun
Jae Geun
JG
Sung
In Kyung
IK
Son
Hee Jung
HJ
Rhee
Poong-Lyul
PL
Kim
Jae J
JJ
Paik
Seung Woon
SW
Rhee
Jong Chul
JC
Choi
Kyoo Wan
KW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D002455:Cell Division / Q000502:physiology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000032:analysis; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D012004:Rectal Neoplasms / Q000737:chemistry / Q000473:pathology*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53