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Objective: To evaluate the effectiveness of bone suppression imaging (BSI) software in lung-nodule detection on chest radiographs (CXRs) in relation to nodule location and observer's experience., Materials and Methods: The CXRs of 80 patients, of which 40 had a lung nodule (8 to 30 mm in diameter) and 40 did not have any nodules, were interpreted by 20 observers comprising of 7 pulmonologists with >10 years of experience and 13 pulmonology residents. Each patient's image was sequentially read, first using the standard CXR and thereafter with the BSI software. The nodule location and confidence level with regard to the presence of a lung nodule were recorded. Receiver operating characteristic analysis was used to evaluate observer performance., Results: The average area under the curve (AUC) for the observers' receiver operating characteristic significantly improved from 0.867 to 0.900 (P=0.004) with the use of the BSI software. The average AUC for experienced pulmonologists improved from 0.877 to 0.924 (P=0.017) for lung nodules located in the apical and peripheral areas but not for those in the inner area. The average AUC for residents improved regardless of nodule location., Conclusion: The use of BSI software improved the performance in lung-nodule detection on CXRs regardless of observer's experience and was more effective for observers with limited experience.

Metastasis and growth in neoplastic lesions requires the multistep regulation of microenvironmental factors. We aimed to elucidate the microenvironmental changes in the process of lymphatic metastasis of lung squamous cell carcinoma. We examined the morphological characteristics of 102 cases of primary tumor (PT), 50 of intralymphatic tumor (ILT), 51 of lymph node (LN) micrometastasis (LN-Mic; ≤2 mm in size), and 82 of LN macrometastasis (LN-Mac; ≥10 mm in size). Afterwards we evaluated the expression of nine molecules (epidermal growth factor receptor, fibroblast growth factor receptor 2, CD44, aldehyde dehydrogenase 1, Podoplanin, E-cadherin, S100A4, geminin, and ezrin) in matched PT, ILT, LN-Mic, and LN-Mac from 23 of these cases. The number of smooth muscle actin α-positive fibroblasts, CD34-positive microvessels and CD204-positive macrophages were also examined. As a result, the mitotic index of tumor cells was significantly lower in ILT and LN-Mic than PT and LN-Mac (P < 0.001). Moreover, stromal reaction in ILT and LN-Mic was less prominent than in PT and LN-Mac (P < 0.001). Immunohistochemical study revealed that epidermal growth factor receptor expression level and frequency of geminin-positive cells in ILT and LN-Mic were significantly lower than in PT and LN-Mac (P < 0.05). The number of stromal cells indicated by staining of CD34, CD204, and smooth muscle actin α in ILT and LN-Mic was also significantly lower than in PT and LN-Mac (P < 0.05). In lung squamous cell carcinoma, drastic microenvironmental changes (e.g., growth factor receptor expression and proliferative capacity of tumor cells and structural changes in stromal cells) occur during both the process of lymphatic permeation and the progression into macrometastases., (© 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Purpose: The expansion of micrometastatic tumors to macrometastatic ones is thought to be tightly regulated by several microenvironmental factors. The aim of this study was to elucidate the morphological and phenotypical differences between micrometastatic and macrometastatic tumors., Method: We first examined the morphological characteristics of 66 lymph node (LN) micrometastatic tumors (less than 2 mm in size) and 51 macrometastatic tumors (more than 10 mm in size) in 42 lung adenocarcinoma cases. Then, we evaluated the expression level of E-cadherin, S100A4, ALDH1, and Geminin in cancer cells and the number of smooth muscle actin (SMA), CD34, and CD204 (+) stromal cells in the primary tumors, matched micrometastatic tumors, and macrometastatic tumors (n = 34, each)., Results: Tumor budding reflects the process of EMT, and stromal reactions were observed more frequently in macrometastatic tumors (P < 0.001). E-cadherin staining score for the micrometastatic tumors was significantly higher than that for the primary tumors (P < 0.001). In contrast, the E-cadherin staining score for the macrometastatic tumors was significantly lower than that for the micrometastatic tumors (P = 0.017). As for the stromal cells, the numbers of SMA (+) fibroblasts, CD34 (+) microvessels, and CD204 (+) macrophages were significantly higher for the macrometastatic tumors and primary tumors than for the micrometastatic tumors (P < 0.001, all)., Conclusion: The present study clearly showed that dynamic microenvironmental changes (e.g., EMT-related changes in cancer cells and structural changes in stromal cells) occur during the growth of micrometastases into macrometastases.

Most primary lung adenocarcinomas show histological diversity, however, histological diversity in the metastatic lymph node tumors (LNT) is not well defined. The aim of this study was to explore the histological characteristics of the metastatic LNT based on their sizes. We analyzed 163 primary tumors and 509 metastatic LNTs. When the primary tumor showed papillary-predominant subtype, the most frequent histological subtype in the metastatic LNT that were ≤2 mm in diameter was solid subtype (49%), followed by papillary subtype (35%); on the other hand, in the metastatic LNT measuring >2 mm in size, the frequency of tumors showing papillary-predominant subtype increased significantly to 52% (P = 0.04). When the primary tumor showed acinar-predominant subtype, the most predominant subtype in the ≤2 mm metastatic LN tumors was acinar subtype (55%), followed by solid subtype (40%), with the frequency of acinar subtype increasing significantly to 76% in the metastatic LNT that were >2 mm in diameter (P = 0.04). These results indicate that solid subtype is the characteristic histological subtype in the early phase of the LN metastatic process, and that as the metastatic LNT grow larger, they develop morphological features resembling those in the primary tumor., (© 2014 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)