{
  "abstract": "Background This study assessed the feasibility of PD-L1 detection via ThinPrep cytology and explored its application in cerebrospinal fluid (CSF) from leptomeningeal metastasis (LM) patients.Methods Six human tumor cell lines (lung, breast and gastric) with validated high/low PD-L1 expression were prepared using ThinPrep cytology and cell-block sections. PD-L1 immunocytochemistry/immunohistochemistry were performed using four antibodies. CSF samples from LM patients were ThinPrep-processed and PD-L1 immunocytochemistry stained. PD-L1 expression was assessed via tumor proportion score (TPS). Inter-assay concordance was evaluated using Cohen’s κ statistics.Results High PD-L1 expression cell lines (NCI-H358, MDA-MB-231, SGC-7901) showed strong staining (TPS: 94-100%) with both 22C3 (Dako) and SP263 (Ventana) assays, while low-expressing lines (A549, MCF7, AGS) had TPS <1%. High concordance was demonstrated between ThinPrep slides and cell-block sections in these two antibodies. The other two antibodies (28-8 and SP142 Abcam) produced false-positive staining in the low-PD-L1-expressing cell line. 122 CSF samples from 61 LM patients (53 lung, 6 breast, and 2 gastric cancers) were detected by 22C3 and SP263. Overall PD-L1 positivity rates were 46% (28/61) with 22C3 and 51% (31/61) with SP263 (κ=0.83). Among these samples, 64 slides contained ≥100 tumor cells, with PD-L1 positivity rates of 50% (16/32) for 22C3 and 56% (18/32) for SP263 (κ=0.88). The remaining 58 slides contained 20-100 tumor cells, with PD-L1 positivity rates of 41% (12/29) for 22C3 and 45% (13/29) for SP263 (κ=0.79). All breast/gastric cancer cases were negative. Lung adenocarcinoma cases showed 53% (28/53) for 22C3 and 58% (31/53) for SP263 positivity (κ=0.81). Among 28 patients with paired extracranial samples, PD-L1 expression concordance rates between CSF and extracranial samples were 57% (16/28) with 22C3 and 61% (17/28) with SP263. For 24 patients receiving intrathecal immunotherapy, the correlation between PD-L1 expression and prognosis is being evaluated during follow-up.Conclusions PD-L1 immunocytochemistry using ThinPrep cytology with 22C3 (Dako) and SP263 (Ventana) in CSF samples from LM patients demonstrated feasibility and potential clinical significance.",
  "authors": [
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Guozi Yang"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Zhenyu Pan"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Hang Lei"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Yushan Huang"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Min Liu"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Miaomiao Liu"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Panpan Tai"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Xiao Chen"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Yuancheng Zhang"
    },
    {
      "affiliations": [
        "The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, Guangdong, China"
      ],
      "name": "Lishi Wang"
    }
  ],
  "title": "127 Detection of PD-L1 in cerebrospinal fluid of leptomeningeal metastasis from solid tumors based on ThinPrep cytology",
  "uid": "727cddea-5366-520a-a0b3-e4c982aac350"
}