A Novel Ploidy Typing of Flow Cytometric DNA Histogram for the Detection of DNA Heterogeneity

Tsutomu Isa, Ken Nomura, Syuji Tomita, Osamu Tamai, Tsuyoshi Teruya, Shigeru Deguchi, Toshiomi Kusano, Yoshihiro Muto

First Department of Surgery, Ryukyu University School of Medicine

A novel ploidy typing of flow cytometric DNA histograms by measurement of single mixed specimens was devised for accurate detection of intratumoral DNA heterogeneity. The results were compared with those obtained by static cytofluorometry (SCM) to investigate the accuracy of this method, and its relationship to clinicopathological findings and prognosis in 30 cases of colon cancer was investigated. To simulate the DNA histogram by computer, the aneuploid pattern was divided into A1 and A2 patterns by the coefficient of variation of the aneuploid peak. Nine of ten diploid pattern cases (90%) showed homogeneity by SCM, and ten of 12 A2 pattern cases (83.3%) showed heterogeneity by SCM. The results with this method were consistent with the results obtained by SCM. Tumors with the A2 pattern showed a tendency toward higher frequency of liver metastasis, lymph node metastasis and a more advanced stage. This ploidy typing might be useful for detection of heterogeneity and investigation of the relationship to clinicopathological findings and prognosis.

Key words
hete ogeneity, ploidy typing of DNA histogram, flow cytometry, static cytofluorometry, colon cancer

Reprint requests
Tsutomu Isa The First Department of Surgery, Ryukyu University School of Medicine
207 Uehara, Nishihara-cho, Okinawa, 903-01 JAPAN

Accepted
May 11, 1993

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