Relationship between p53, p21 and Apoptosis in Colorectal Cancer

Kenji Katsumata, Tetsuo Sumi, Keiichiro Yamamoto, Sou Katayanagi, Takashi Murohashi, Kazuhiro Nagashima, Tatsuto Ashizawa, Yasuhisa Koyanagi^*, Tatsuya Aoki^* and Koichirou Katoh^*

Department of Gastroenterological Surgery Hachioji Medical Center, Tokyo Medical College ^*Department of Surgery Tokyo Medical College

In 92 colon cancer patients, point mutation of the p53 gene and expression of the p21 gene were determined to discuss about appearance of apoptosis. Point mutation of the p53 gene was determined by PCR-SSCP. p21 expression was determined positive upon immunostaining when more than 20% of the nucleus in cancer cells were stained. Apoptosis was detected by DNA ladder sequencing. No correlation was noted between the presence of p53 gene mutation, expression of p21 gene and pathological factors, nor was correlation noted between p53 gene mutation and p21 gene staining rate, by apperance of DNA ladder. However a certain trend was observed in those cells with p21 positive staining showing the least appearance of DNA ladder (p<0.0115). Among those without p53 gene mutation, DNA ladder did not appear when those p21 staining was positive, and it was noted much when p21 staining was negative (p<0.0015). From the above findings, it is known that in the presence of the p21 gene DNA in repaired and induces no apoptosis, and that when the p53 gene functions normally, such a trend is further accelerated by the p21 gene.

Key words
colon cancer, p53, p21, apoptosis, DNA ladder

Reprint requests
Kenji Katsumata Department of Gastroenterological Surgery Hachioji Medical Center, Tokyo Medical College 1163 Tatemachi, Hachioji, 193-0944 JAPAN

Accepted
July 25, 2000

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