Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc
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To determine whether tumor microenvironments affect the clinical response to anti-PD-1 therapy in non-small cell lung cancer, we investigated the expression level of PD-L1 and tumor infiltrating lymphocytes and elucidate their predictive role. Thirty-eight pretreatment and two post-treatment specimens from 36 advanced, treatment-refractory non-small cell lung cancer patients who underwent PD-1 blockade therapy were analyzed. PD-L1 expression by tumor cells and the distribution of CD3, CD8, CD4, FOXP3 and PD-1 positive tumor infiltrating lymphocytes were immunohistochemically assessed and counted using digital image analyzer. ⋯ Using receiver operating characteristic curves, levels of CD3+ T cells and FOXP3+/CD8+ T cell ratio that provide the best distinguishing point between responder versus non-responder to PD-1 blockade were 617.5/mm2 and 25%, respectively (p = 0.007 and p = 0.003). Considering that 1 mm2 is about 5 high power fields (HPF), a good response to the PD-1 blockade can be expected when the number of CD3 T cells is observed to be 120 per HPF and when CD8+ T cells and FOXP3+ T cells are present at a ratio greater than 4:1. Tumor infiltrating lymphocytes might become a promising biomarker as an independent predictive factor of response to PD-1 blockade that may also guide therapeutic decisions.
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Skeletal muscle tumors are traditionally classified as rhabdomyoma or rhabdomyosarcoma. We have identified an unusual adult rhabdomyoblastic tumor not clearly corresponding to a previously described variant of rhabdomyoma or rhabdomyosarcoma, characterized by a very striking proliferation of non-neoplastic histiocytes, obscuring the underlying tumor. Ten cases were identified in nine males and one female with a median age of 43 years (range 23-69 years). ⋯ At the time of last follow-up, all patients were alive and without disease; no local recurrences or distant metastases occurred. We hypothesize that these unusual tumors represent rhabdomyoblastic tumors of uncertain malignant potential. Possibly over time they should be relegated to a new category of skeletal muscle tumors of intermediate (borderline) malignancy.