Introduction
Cancer‐associated fibroblasts (CAFs) in the tumour microenvironment play a key role in tumour development, proliferation, invasion, and metastasis. The cytological features of spindle ...cells including CAFs—defined as stromal spindle cells (SSCs) adjacent to cancer cells—are frequently encountered in pulmonary adenocarcinomas. This study aimed to investigate the association between the presence of SSCs in cytological specimens and the clinicopathological features.
Methods
We evaluated 211 patients with pulmonary adenocarcinoma who underwent surgical resection. All participants had cytological specimens corresponding to the histological specimens available for review.
Results
Of the 211 cases examined, 89 were SSC‐positive (SSC+) and 122 were SSC‐negative (SSC−). SSC+ cases were more frequently associated with higher pathological stage (P < 0.001), lymph node metastasis (P = 0.002), anaplastic lymphoma kinase (ALK) gene rearrangement (P = 0.04), high tumour grade (P < 0.001), solid and micropapillary predominant pattern (P = 0.02), and lymphatic vessel (P = 0.003), blood vessel (P < 0.001), and pleural invasion (P = 0.03) as compared to SSC− cases. Patients with SSC+ adenocarcinoma had a significantly shorter recurrence‐free survival than those with SSC− adenocarcinoma (P = 0.009). Cytologically, necrotic background (P = 0.002), mucinous cancer cells (P = 0.02), pleomorphic cells (P < 0.001), and mutual cell inclusions (P = 0.01) were observed more frequently in SSC+ adenocarcinomas.
Conclusions
The presence of SSCs could be an important cytological feature for predicting poor prognosis in lung adenocarcinomas.
Cancer‐associated fibroblasts (CAFs) surrounding cancer cells play a key role in determining patient prognosis. Stromal spindle cells including CAFs are frequently observed intermixed with cancer cells in cytological specimens and their presence could be an important cytological marker for predicting poor prognosis in lung adenocarcinomas.
Anaplastic lymphoma kinase‐rearranged (ALK+) lung cancers show characteristic histological features, such as solid signet ring cell patterns and mucinous cribriform patterns; however, these features ...are not always observed in ALK+ lung cancers. We noticed that club cell (Clara cell)‐like cells (CLCs) were frequently present in the papillary portion of ALK+ lung adenocarcinomas. In this study, we investigated the importance of CLCs in papillary patterns of ALK+ lung cancers. We compared the histological features of 18 ALK+ cases with 62 control cases (22 epidermal growth factor receptor‐positive (EGFR+) and 40 ALK‐ and EGFR‐negative (ALK−/EGFR−) cases). The present study analyzed presence of papillary pattern, proportion of papillary pattern area, presence of micropapillary pattern, frequency of CLCs and lengths of snout. The frequency of CLCs in ALK+ cases was significantly higher than that in EGFR+ cases and ALK−/EGFR− cases. Micropapillary pattern was more frequently observed in ALK+ cases than that in ALK−/EGFR− cases (P < 0.001). The present study indicated that the high frequency of CLCs in papillary patterns was significantly associated with ALK+ cases. When solid signet ring cell patterns and mucinous cribriform patterns are absent, the high frequency of CLCs in papillary adenocarcinoma could be a useful histological marker for ALK+ lung cancers.
