Site-Specific Factor 5

Chromosome 1p: Loss of Heterozygosity (LOH)


**Note 1:** This is a special molecular diagnostic test performed on tumor tissue to identify loss of genetic material normally found on the short arm of one of the patient's two copies of chromosome 1. A normal cell will contain two complete copies of each chromosome, one from each parent, and this normal state is termed heterozygous. Loss of heterozygosity (LOH) is an abnormal state reflecting damage to the chromosome. **Note 2:** Other terms for LOH include gene deletion and allelic loss. **Note 3:** For brain tumors, tests for LOH of chromosomes 1p and 19q may be performed at the same time and reported on a single report. See also Site-Specific Factor 6.




NAACCR #2920


Code Description
010 Test positive for loss of heterozygosity (LOH)
020 Test negative for LOH
988 Not applicable: Information not collected for this case
997 Test ordered, results not in chart
998 No histologic examination of primary site
Test not done (test not ordered and not performed)
999 Unknown or no information
Not documented in patient record