INVESTIGATION OF SPECIMEN MISLABELING IN PARAFFIN-EMBEDDED TISSUE USING A RAPID, ALLELE-SPECIFIC, PCR-BASED HLA CLASS-II TYPING METHOD

Mislabelling of surgical specimens can seriously affect the accuracy o f histopathology reports. We describe two cases in which clinically su spected mislabelling was investigated by polymerase chain reaction (PC R)-based HLA DRB and DQB tissue typing of paraffin biopsy-derived DNA, using sequence specific primers (PCR-SSP HLA typing). In the first ca se, two patients underwent surgery for breast carcinoma. A subcutaneou s lymph node containing metastatic carcinoma was received with the bre ast specimen from one patient, but was clinically considered more like ly to originate from the other patient who underwent breast surgery on the same day. In the second case, histological examination of retaine d products of conception from a young woman revealed adenocarcinoma, b ut a repeat curettage specimen consisted of secretory phase endometriu m. In case 1, PCR-SSP HLA typing confirmed the clinical suspicion that the subcutaneous lymph node received with tissue from one patient ori ginated from the other patient, This result converted the first patien t from lymph node positive breast carcinoma to lymph node negative dis ease. In case 2, there was no evidence from PCR-SSP HLA typing that th e endometrial samples had originated from different patients. PCR-SSP HLA typing requires fewer steps than methods based on PCR amplificatio n followed by oligonucleotide probing (PCR-SSOP HLA typing), and relie s on the amplification of shorter sequences of DNA. Therefore, this te chnique can produce more rapid results than PCR-SSOP HLA typing, and i s ideally suited to typing partially degraded DNA derived from formali n-fixed and paraffin-embedded tissue.