Whole-Section Landscape Analysis of Molecular Subtypes in Curatively Resected Small Cell Lung Cancer: Clinicopathologic Features and Prognostic Significance.

Despite the recognition of various molecular subtypes in small cell lung cancer (SCLC), most information has been derived from tissue microarrays or biopsy samples. Using whole sections of curatively resected SCLCs, we aimed to elucidate the clinicopathologic relevance and prognostic significance of the molecular subtypes. Whole-section immunohistochemistry was conducted for 73 resected SCLC samples using antibodies representative of molecular subtypes: ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POU2F3 (SCLC-P), and YAP1. Furthermore, multiplexed immunofluorescence was performed to evaluate the spatial relationship of YAP1 expression with other markers. The molecular subtype was correlated with clinical and histomorphologic features, and its prognostic role was explored in this cohort and validated in a previously published surgical cohort. Overall, the molecular subtypes were SCLC-A (54.8%), SCLC-N (31.5%), SCLC-P (6.8%), and SCLC-TN (triple negative, 6.8%). We found significant enrichment of SCLC-N (48.0%; P = .004) among combined SCLCs. Although a distinct subtype with high YAP1 expression was not found, YAP1 expression was reciprocal with ASCL1/NEUROD1 at the cellular level within tumors and was increased in areas with non-small cell-like morphology. Furthermore, the YAP1-positive SCLCs showed significantly increased recurrence at mediastinal lymph nodes (P = .047) and are an independent poor prognostic factor after surgery (adjusted hazard ratio, 2.87; 95% CI, 1.20-6.86; P = .017). The poor prognostic impact of YAP1 was also validated in the external surgical cohort. Our whole-section analysis in resected SCLCs reveals the highly heterogeneous nature of the molecular subtype and its clinicopathologic relevance. Although YAP1 is not a subtype delineator, YAP1 relates to the phenotypic plasticity of SCLC and may serve as a poor prognostic factor in resected SCLC.

The role of 18F-FDG PET/CT for initial staging of nasal type natural killer/T-cell lymphoma: a comparison with conventional staging methods.

UNLABELLED: The utility of (18)F-FDG PET/CT in patients with nasal-type natural killer (NK)/T-cell lymphoma has not been established. Therefore, we evaluated the role of (18)F-FDG PET/CT for determining cancer staging by comparing its results to those of conventional staging methods (CSMs) (physical examination, CT with intravenous contrast, biopsies from primary sites, and bone marrow examinations) in patients with nasal-type NK/T-cell lymphoma. METHODS: In this study, 52 consecutive patients (34 men, 18 women; mean age, 49.4 y) with newly diagnosed nasal-type NK/T-cell lymphoma were studied. Anatomic regions (n = 1,300; 16 nodal and 9 extranodal regions per patient) were assessed with an (18)F-FDG PET/CT scan and with CSMs, and each anatomic region was classified as positive or negative for malignancy. Biopsy and clinical follow-up, including additional imaging studies, were used as the gold standard for diagnosis. RESULTS: Of the 59 nodal and 71 extranodal anatomic regions that were truly positive for malignancy, (18)F-FDG PET/CT detected 58 nodal and 69 extranodal. CSMs, however, detected only 44 of the nodal and 61 of the extranodal anatomic regions that were positive for malignancy (nodal comparison of PET/CT vs. CSMs, P < 0.001; extranodal comparison of PET/CT vs. CSMs, P = 0.008). PET/CT scans exhibited a significantly better sensitivity (97.7% vs. 80.7%, P < 0.001) than CSMs for the detection of malignant lesions. PET/CT findings altered the original staging category for 12 patients (21.2%) and affected treatment planning in 23 cases (44.2%). CONCLUSION: Our study demonstrated that (18)F-FDG PET/CT scanning is a valuable modality for staging and treatment planning in patients with nasal-type NK/T-cell lymphoma.