医療を支える病理診断 : 第260回徳島医学会学術集会市民公開シンポジウムより

Pathological diagnosis is useful for the personalization of cancer treatment including that for breast cancer. Breast cancer is subtyped by hormone receptors, Ki-６７ and human epidermal growth factor receptor ２（HER２）. Immunohistochemistry of tumor specimens is performed to determine the expression of these factors, with different treatments administered for each subtype, such as endocrine therapy, HER２-targeted therapy and chemotherapy. In addition, to ascertain the indications for immune checkpoint inhibitors, the status of programmed death ligand １（PD-L１）on tumor-infiltrating immune cells is also determined by the histopathology of specimens.
Pathologists examine the effects of neoadjuvant treatment on patient samples obtained during surgery. Such information is useful for guiding the selection of subsequent appropriate therapeutic strategies.
Cancer genomic panels using formalin-fixed, paraffin-embedded（FFPE）blocks of pathological samples enable the examination of many important genes and biomarkers that may indicate if a targeted therapy or a clinical trial is suitable for that patient. Clinicians, pathologists, and laboratory technicians work together to correctly handle such specimens to prevent the deterioration of the nucleic acid contained within the blocks. Pathologists review sections of samples on glass slides to assess the sample quality and enable selection of the optimal FFPE blocks. Evaluating tumor content and indicating tumorous regions within sections are also important tasks for pathologists. Furthermore, the suitability of any potential therapy is discussed with the pathologists based on their findings.
Routine pathological diagnosis and cancer genome diagnosis are closely related, and pathologists require knowledge of genomic diagnosis technology. However, the most important aspect for optimal treatment is a quick and accurate pathological diagnosis to support the provision of high-quality medical care.