[Evaluation of the criterion of partial loss of heterozygous in tumor tissues].

Objective: To evaluate the applicability of partial loss of heterozygous (pLOH) criteria in tumor tissues with Identifiler system.

Methods: Eight thousand four hundred and twenty eight heterozygous loci of the 696 unrelated individuals (UIP) genotyped with Identifiler Kit were randomly paired by locus to construct odds ratio of allelic peak height (or area under allelic curve) according to the given formula. Similarly, odds ratios of allelic peak height (or area under allelic curve) of the 896 heterozygous loci of 77 pairs of tumor and homologous normal tissues (TNP) were also acquired. Curve fitting was performed to determine the distribution of the odds ratio. The proportion of pLOH in two groups was determined with odds ratio less than 0.5 or higher than 2.0. Compared the relevance ratio of allelic peak height and peak area by chi2 test.

Results: The odds ratio of both peak height and peak area presented normal distribution in UIP (4214 heterozygous loci pairs) and TNP group (896 heterozygous loci pairs). There was 0.12% of normal heterozygous in UIP group erroneously presumed as pLOH with current criteria (< 0.5 or > 2.0). There was no significantly difference between the calling rate based on two types of odd ratio (P = -0.5632).

Conclusion: It is feasible to determine the pLOH in tumor tissue with Identifiler system by both peak height and peak area according to the standards of the odds ratio less than 0.5 or higher than 2.0.