Validation of Pathologic Diagnosis of Invasive Fungal Infection by Molecular Method

Validation of Pathologic Diagnosis of Invasive Fungal Infection by Molecular Method - Retrospective Study Using Residual Storage Tissue Specimen

1. Isolate fungal DNA(Deoxyribonucleic acid) from paraffin-fixed tissue specimens to distinguish and compare Aspergillus species to the existing optical pathological diagnosis.
2. PCR(polymerase chain reaction) validation.
3. Compare PCR results, microbial results and treatment results with the medical record.

This study is a retrospective PCR(polymerase chain reaction) analysis of paraffin-fixed sample with a participants chart review. The PCR analysis will consist of two phases; a PCR test validation phase and an azole resistance test phase. The investigators will also perform a retrospective chart review to investigate the association of participants' fungal clinical outcomes and the presence of azole resistance.

I. PCR analysis

1. PCR test validation phase

   • Validating PCR assay by mock tissues and Invasive fungal infection proven tissues(microbiologically and pathologically proven cases).
   • The number of validation samples will be 1000 (200 samples * five target PCR).
   • For the enough validation of PCR results, inter-laboratory comparisons, especially with the core laboratory, are performed to verify the PCR results of the same test sample among laboratories and to standardize a certain protocol for the molecular identification of fungal infection from the clinical specimens.
   • Positive controls (human β-globin gene and mouse actin gene) and negative controls (non-infected samples) are used for validating of PCR assays. Precision of each PCR set is checked using the false discovery rate (FDR) which can be the acceptable level of false positives among a set of significant results. If FDR is >5%, it will be rejected.
   • The intra-assay repeatability will be evaluated on 10 replicates of one of the DNA subsamples analyzed in a single assay. The inter-assay reproducibility will be assess on the same DNA subsample five separate times while the inter-sample reproducibility will be determine on separate extractions of the four subsamples amplified a single time. Statistical analysis will be carry out using SAS software.

2. Azole resistance test phase

   • The investigator will perform a PCR assay using participants biopsied paraffin embedded tissues. Technical method of the PCR assay is attached separately.
   • Around a hundred biopsied samples under impression of fungal infection from June 1st, 2009 to June 31st, 2014 will be included for the PCR testing.

II. Retrospective chart review of all enrolled participants.

1. Data collection

   • All available participants' electronic medical record data will be reviewed for collecting demographic and clinical information.

2. Outcome measures

   • The investigators will evaluate Invasive fungal infecrion treatment results, survival rates, and prognosis according to the existence of azole resistance and antifungal treatment modalities including medications.

Inclusion Criteria:

• Patients who were diagnosed with invasive fungal disease based on the biopsy from June 2009 to May 2014

Exclusion Criteria:

• Patients who do not currently have residual paraffin-fixed specimens