Loss of heterozygosity at chromosome 1p in different solid human tumours: association with survival

The distal half of chromosome 1p was analysed with 15 polymorphic microsate llite markers in 683 human solid tumours at different locations. Loss of he terozygosity (LOH) was observed at least at one site in 369 cases or 54% of the tumours. LOHs detected ranged from 30-64%, depending on tumour locatio n. The major results regarding LOH at different tumour locations were as fo llows: stomach, 20/38 (53%); colon and rectum, 60/109 (55%); lung, 38/63 (6 0%); breast, 145/238 (61%); endometrium, 18/25 (72%); ovary, 17/31 (55%); t estis, 11/30 (37%); kidney, 22/73 (30%); thyroid, 4/14 (29%); and sarcomas, 9/14 (64%). High percentages of LOH were seen in the 1p36.3, 1p36.1, 1p35- p34.3, 1p32 and 1p31 regions. suggesting the presence of tumour-suppressor genes. All these regions on chromosome 1p show high LOH in more than one tu mour type. However, distinct patterns of LOH were detected at different tum our locations. There was a significant separation of survival curves, with and without LOH at chromosome 1p, in the breast cancer patients. Multivaria te analysis showed that LOH at 1p in breast tumours is a better indicator f or prognosis than the other variables tested in our model, including nodal metastasis.