Differential oxygen sensitivities in G6PDH activities of cultured keloid and normal skin dermis single cells

Cell cultures of excised keloids and biopsied normal skin were established from patients of the Plastic Surgery Department of Singapore General Hospital and their single cells quantitated for glucose-6-phosphate dehydrogenase (G6PDH) activity using microspectrophometry. G6PDH has been cited as a transformation-linked discriminant. Analysis of variance shows no difference in overall activity between skin and keloid cells, but under oxygen saturation conditions, keloid G6PDH activity was significantly higher than skin G6PDH activity, although they were almost identical under nitrogen saturation conditions. Differential oxygen sensitivity in G6PDH activities between malignant and non-malignant cells have been reported, but its occurrence between keloid and normal skin cells is novel, especially as the keloid is regarded as a benign tumor with a zero carcinogenicity rate.