Repair of DNA damaged by methylmethane sulfonate in normal human lymphocytes and in xeroderma pigmentosum

: Methylmethanesulphonate has been shown to stimulate an intensive unscheduled DNA synthesis in lymphocytes derived from normal donors as well as in those from patients with xeroderma pigmentosum of the classical form. Somewhat less intensive unscheduled DNA synthesis was observed in cells of a patient suffering from xeroderma pigmentosum. In the case of XPII unscheduled DNA synthesis was greatly reduced which supports the peculiarity of this form of xeroderma pigmentosum.