A novel histopathological feature of spatial tumor-stroma distribution predicts lung squamous cell carcinoma prognosis.

We used a mathematical approach to investigate the quantitative spatial profile of cancer cells and stroma in lung squamous cell carcinoma tissues and its clinical relevance. The study enrolled 132 patients with 3-5 cm peripheral lung squamous cell carcinoma, resected at the National Cancer Center Hospital East. We utilized machine learning to segment cancer cells and stroma on cytokeratin AE1/3 immunohistochemistry images. Subsequently, a spatial form of Shannon's entropy was employed to precisely quantify the spatial distribution of cancer cells and stroma. This quantification index was defined as the spatial tumor-stroma distribution index (STSDI). The patients were classified as STSDI-low and -high groups for clinicopathological comparison. The STSDI showed no significant association with baseline clinicopathological features, including sex, age, pathological stage, and lymphovascular invasion. However, the STSDI-low group had significantly shorter recurrence-free survival (5-years RFS: 49.5% vs. 76.2%, p < 0.001) and disease-specific survival (5-years DSS: 53.6% vs. 81.5%, p < 0.001) than the STSDI-high group. In contrast, the application of Shannon's entropy without spatial consideration showed no correlation with patient outcomes. Moreover, low STSDI was an independent unfavorable predictor of tumor recurrence and disease-specific death (RFS; HR = 2.668, p < 0.005; DSS; HR = 3.057, p < 0.005), alongside the pathological stage. Further analysis showed a correlation between low STSDI and destructive growth patterns of cancer cells within tumors, potentially explaining the aggressive nature of STSDI-low tumors. In this study, we presented a novel approach for histological analysis of cancer tissues that revealed the prognostic significance of spatial tumor-stroma distribution in lung squamous cell carcinoma.

Posttreatment Head and Neck Cancer Imaging: Anatomic Considerations Based on Cancer Subsites.

Posttreatment imaging surveillance of head and neck cancer is challenging owing to complex anatomic subsites and diverse treatment modalities. Early detection of residual disease or recurrence through surveillance imaging is crucial for devising optimal treatment strategies. Posttreatment imaging surveillance is performed using CT, fluorine 18-fluorodeoxyglucose PET/CT, and MRI. Radiologists should be familiar with postoperative imaging findings that can vary depending on surgical procedures and reconstruction methods that are used, which is dictated by the primary subsite and extent of the tumor. Morphologic changes in normal structures or denervation of muscles within the musculocutaneous flap may mimic recurrent tumors. Recurrence is more likely to occur at the resection margin, margin of the reconstructed flap, and deep sites that are difficult to access surgically. Radiation therapy also has a varying dose distribution depending on the primary site, resulting in various posttreatment changes. Normal tissues are affected by radiation, with edema and inflammation occurring in the early stages and fibrosis in the late stages. Distinguishing scar tissue from residual tumor becomes necessary, as radiation therapy may leave behind residual scar tissue. Local recurrence should be carefully evaluated within areas where these postradiation changes occur. Head and Neck Imaging Reporting and Data System (NI-RADS) is a standardized reporting and risk classification system with guidance for subsequent management. Familiarity with NI-RADS has implications for establishing surveillance protocols, interpreting posttreatment images, and management decisions. Knowledge of posttreatment imaging characteristics of each subsite of head and neck cancers and the areas prone to recurrence empowers radiologists to detect recurrences at early stages. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Imaging of salivary gland cancers derived from a sublingual gland herniated into the submandibular space: a report of three cases.

Sublingual gland herniation into the submandibular space through a mylohyoid muscle defect is a common anatomical variation; however, salivary gland cancers that arise from a herniated sublingual gland have not been described yet. Here, we report three patients with salivary gland cancers originating from a herniated sublingual gland. All tumors were detected as palpable submandibular masses, located anterior to the submandibular gland, medial to the mandible, and lateral to the mylohyoid muscle, with contact with the sublingual gland through a mylohyoid muscle defect. Intraoperative findings confirmed that the masses were derived from herniated sublingual glands. Pathological examination showed one case of mucoepidermoid carcinoma and two cases of adenoid cystic carcinoma. Imaging findings of the tumor location, in addition to the continuity with the sublingual gland through the mylohyoid muscle defect, are crucial for accurately diagnosing the tumor origin, which is essential for determining the appropriate clinical management.

Common clinicopathological and immunological features of sarcomatoid carcinoma across organs: A histomorphology-based cross-organ study.

Sarcomatoid carcinoma (SC), which can occur in any organ, is a rare disease. To elucidate common characteristics of SC beyond organs, we evaluated clinicopathological and immunological features of SC defined by the single histological criterion beyond organs compared to randomly matched conventional carcinoma (non-SC) adjusted for the disease stage. Immunological features were assessed by multiplex immunohistochemistry, comparing immune cell density in tumor tissues and tumor programmed death-ligand 1 (PD-L1) expression. A total of 101 patients with SC or non-SC (31 lung, 19 esophagus, 22 pancreas, 15 liver, 4 bile duct, 6 kidney, 2 uterus and 2 ovary) were identified among 7197 patients who underwent surgery at our institute (1997-2020). SC was significantly associated with worse survival (HR: 1.571; 95% CI: 1.084-2.277; P = .017). The frequency of postoperative progression within 6 months was significantly higher for SC patients (54% vs 28%; P = .002). The immune profiling revealed the densities of CD8+ T cells (130 vs 72 cells/mm2 ; P = .004) and tumor-associated macrophages (566 vs 413 cells/mm2 ; P < .0001) and the tumor PD-L1 expression score (40% vs 5%; P < .0001) were significantly higher in SCs than in non-SCs. Among 73 SC patients with postoperative progression, multivariate Cox regression analysis showed that immunotherapy tended to be associated with favorable survival (HR: 0.256; 95% CI: 0.062-1.057; P = .060). Collectively, SCs shared clinicopathological and immunological features across organs. Our study can initiate to standardize the pathological definition of SC and provide a rationale for the investigation and development for this rare disease in a cross-organ manner.

Clinicopathological features and prognostic impact of dirty necrosis in metastatic lung cancers from the colon and rectum.

Dirty necrosis (DN) is a form of tumor necrosis (TN) with prominent neutrophil infiltration and cell detritus in the necrotic foci. This study aimed to characterize the clinicopathological features of DN in metastatic lung cancers of the colon and rectum (MLCRs). A total of 227 patients who underwent pulmonary metastasectomy and complete resection for MLCR were included in this study. TN was evaluated using digitally scanned resection specimens. These slides were immunostained for biomarkers of NETosis (citrullinated histone H3 [citH3] and myeloperoxidase [MPO]), and the area positive for citH3 and MPO was further quantified. TN was observed in 216 cases (95.2%), and 54 (25.0%) of these cases had DN. The presence of TN was not associated with a worse prognosis; however, patients with DN had a significantly shorter overall survival than those without DN (p < 0.01). Furthermore, the presence of DN was a poor prognostic factor in both the univariate and multivariate analyses. Immunohistochemical analysis revealed that the percentage of citH3-positive and MPO-positive areas in the DN-positive cases was significantly higher than that in the DN-negative cases (p < 0.01 and p < 0.01, respectively). In surgically resected MLCR, DN is the characteristic TN subtype associated with poor prognosis and neutrophil extracellular traps (NETs).

Prognostic impact and gene expression analysis of peri-tumoral alveolar macrophage in resected lung adenocarcinoma.

The prognostic significance and role of extratumoral alveolar macrophages (exAMs) in lung adenocarcinoma (LUAD) patients remain unknown. In this study, we investigated the prognostic impact and gene expression of exAMs in LUAD patients. The density of alveolar macrophages (AMs) in the peri-tumoral lung field (p-exAMs) and distant lung field (d-exAMs) was evaluated in 217 LUAD patients with lymph node metastasis. Patients with high p-exAMs showed significantly shorter recurrence-free (RFS) and shorter overall survival (OS) than those with low p-exAMs (p = 0.02 and p = 0.03, respectively), whereas there was no survival difference between patients with high d-exAMs and those with low d-exAMs. Multivariate analysis revealed that high p-exAMs was an independent predictive factor for RFS (HR: 1.54; 95% confidence interval [CI]:1.10-2.16; p = 0.01). Later, we collected AMs from the tumor periphery and distant segments in 13 resected lungs by bronchoalveolar lavage (BAL) procedure and compared mRNA expression. AMs in the tumor periphery expressed significantly higher levels of IL-10 and CCL2 than those in the distant segment (p < 0.01 and p = 0.03, respectively). Additionally, IL-10 and CCL2 significantly induced the growth and migration of the PC9 cells in vitro. This study suggests that p-exAMs should be considered as a tumor-promoting component in the tumor microenvironment.

Clinicopathological significance of peritumoral alveolar macrophages in patients with resected early-stage lung squamous cell carcinoma.

INTRODUCTION: This study aimed to clarify the correlation between the number of AMs and prognosis and to examine the gene expression of AMs in lung squamous cell carcinoma (SqCC). METHODS: We reviewed 124 stage I lung SqCC cases in our hospital and 139 stage I lung SqCC cases in The Cancer Genome Atlas (TCGA) cohort in this study. We counted the number of AMs in the peritumoral lung field (P-AMs) and in the lung field distant from the tumor (D-AMs). Moreover, we performed a novel ex vivo bronchoalveolar lavage fluid (BALF) analysis to select AMs from surgically resected lung SqCC cases and examined the expression of IL10, CCL2, IL6, TGFß, and TNFα (n = 3). RESULTS: Patients with high P-AMs had significantly shorter overall survival (OS) (p < 0.01); however, patients with high D-AMs did not have significantly shorter OS. Moreover, in TCGA cohort, patients with high P-AMs had a significantly shorter OS (p < 0.01). In multivariate analysis, a higher number of P-AMs were an independent poor prognostic factor (p = 0.02). Ex vivo BALF analysis revealed that AMs collected from the tumor vicinity showed higher expression of IL10 and CCL2 than AMs from distant lung fields in all 3 cases (IL-10: 2.2-, 3.0-, and 10.0-fold; CCL-2: 3.0-, 3.1-, and 3.2-fold). Moreover, the addition of recombinant CCL2 significantly increased the proliferation of RERF-LC-AI, a lung SqCC cell line. CONCLUSION: The current results indicated the prognostic impact of the number of peritumoral AMs and suggested the importance of the peritumoral tumor microenvironment in lung SqCC progression.

Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma.

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

Imaging Approach for Cervical Lymph Node Metastases from Unknown Primary Tumor.

Neck swelling due to lymph node (LN) metastasis is one of the initial symptoms of head and neck cancer, and in some cases, the primary tumor is not clinically evident. The purpose of imaging for LN metastasis from an unknown primary site is to identify the primary tumor or detect its absence, which leads to the correct diagnosis and optimal treatment. The authors discuss diagnostic imaging approaches for identifying the primary tumor in cases of unknown primary cervical LN metastases. The distribution and characteristics of LN metastases may help locate the primary site. Unknown primary LN metastasis often occurs at nodal levels II and III, and in recent reports, these were mostly related to human papillomavirus (HPV)-positive squamous cell carcinoma of the oropharynx. Another characteristic imaging finding suggestive of metastasis from HPV-associated oropharyngeal cancer is a cystic change in LN metastases. Other characteristic imaging findings such as calcification may help predict the histologic type and locate the primary site. In cases of LN metastases at nodal levels IV and VB, a primary lesion located outside the head and neck region must also be considered. One clue for detecting the primary lesion at imaging is the disruption of anatomic structures, which can help in identifying small mucosal lesions or submucosal tumors at each subsite. Additionally, fluorine 18 fluorodeoxyglucose PET/CT may help identify a primary tumor. These imaging approaches for identifying primary tumors enable prompt identification of the primary site and assist clinicians in making the correct diagnosis. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

The prognostic impact of a high number of peritumoral alveolar macrophages in neuroendocrine carcinoma in the lung.

Alveolar macrophages (AMs) are resident macrophages in the lungs; however, whether the number of AMs plays a role in the lung neuroendocrine tumor (NET) prognosis remains unclear. We counted the number of AMs located around the tumor (peritumoral alveolar macrophages [pAMs]) and the number of AMs located apart from the tumor (distant macrophages; dAMs). In 73 cases of neuroendocrine carcinoma (NEC: small cell lung carcinoma and large cell neuroendocrine carcinoma), the group that contained higher pAMs (≥86/µm2 ) revealed shorter recurrent-free survival (RFS) than those with lower pAMs (<86/µm2 ) (p = 0.005). Bivariate analysis showed that the number of pAMs was an independent predictor of a poor RFS. In contrast, in the carcinoid tumor cohort (n = 29), there was no statistically significant correlation between the two groups with high and low numbers of pAMs in RFS (p = 0.113). Furthermore, we examined the correlation between genomic alterations and the number of pAMs in NEC, but no significant correlation was observed. In conclusion, the number of pAMs is a prognostic factor for NEC in the lung and pAMs may contribute to tumor progression within the peritumoral microenvironment.

Pathologic method for extracting good prognosis group in triple-negative breast cancer after neoadjuvant chemotherapy.

The area of residual tumor (ART) is a prognostic factor in patients treated with neoadjuvant chemotherapy (NAC) for lung, pancreatic, and rectal cancers. This study aimed to evaluate the usefulness of ART as a method for predicting the prognosis of triple-negative breast cancer (TNBC) patients after NAC. We included 143 patients with TNBC treated with NAC. The ART at the maximum cut surface of the residual tumor was measured. We divided the patients into three groups: ART-0 (ART = 0 mm2 ), ART-low (0 mm2  < ART ≤ 136mm2 ), and ART-high (ART > 136 mm2 ), and compared their clinicopathologic factors and prognosis. There were no significant differences in either recurrence-free survival (RFS) or overall survival (OS) between ART-0 and ART-low; however, the ART-high group had significantly shorter RFS and OS than the ART-0 and ART-low groups. Multivariate analysis showed that ART-0 and -low and ypN(-) were independent favorable prognostic factors for RFS. Groups with both ART-low and ypN(-) as well as those with ART-0 and ypN(-) showed significantly longer OS and RFS than the other groups (P < .05). Moreover, there was no significant difference in the RFS and OS between the ART-0 and ypN(-) groups and the ART-low and ypN(-) groups (P = .249 and P = .554, respectively). We concluded that ART is a candidate histopathological evaluation method for predicting the prognosis of TNBC patients treated with NAC. Furthermore, postoperative chemotherapy could be omitted in patients with ART-0 and ypN(-) (pathological complete response) and those with ART-low and ypN(-).

18F-fluorodeoxyglucose uptake in PET is associated with the tumor microenvironment in metastatic lymph nodes and prognosis in N2 lung adenocarcinoma.

Positron emission tomography is a useful technique for diagnosing lymph node (LN) metastasis. This study aimed to elucidate the association between fluorodeoxyglucose accumulation and the microenvironment in metastatic LNs in lung adenocarcinoma. We retrospectively analyzed 62 patients with surgically resected pathological N2 lung adenocarcinoma who underwent preoperative PET. The maximum standardized uptake value (SUVmax ) in the metastatic LNs was measured. Lymph node specimens were immunohistochemically analyzed for CD8+ , FoxP3+ , and CD79a+ lymphocytes, CD204+ tumor-associated macrophages (TAMs), and alpha-smooth muscle actin-positive cancer-associated fibroblasts (αSMA+ CAFs). We compared the clinicopathologic and immunohistochemical characteristics between two groups with high and low LN SUVmax . Using novel 3D hybrid spheroid models, we investigated the change in invasiveness of cancer cells in the presence of CAFs. In the multivariate analyses, LN SUVmax was an independent prognostic factor. The overall survival in the LN SUVmax high group was significantly worse than in the low group (P = .034). In the LN SUVmax high group, metastatic cancer cell invasion of extranodal tissue was more frequent (P = .005) and the number of CD204+ TAMs and αSMA+ CAFs in metastatic LNs was significantly higher than in the low group (P < .001 and P = .002, respectively). Hybrid spheroid models revealed that cancer cells coexisting with CAFs were more invasive than those without CAFs. Our results indicated a strong association between LN SUVmax and poor prognosis in patients with N2 lung adenocarcinoma. Moreover, LN SUVmax was suggested to be associated with the presence of tumor-promoting stromal cells in metastatic LNs.

Prognostic impact of count of extratumoral lymphatic permeation in lung adenocarcinoma and its relation to the immune microenvironment.

Extratumoral lymphatic permeation (ly-ext) has been reported as an independent poor prognostic factor for lung adenocarcinoma, but whether or not the number of ly-ext foci is associated with prognosis and its relationship to the immune microenvironment is unclear. We counted the number of ly-ext foci on pathological slides from patients with completely resected lung adenocarcinoma with ly-ext, and divided them into two groups: a group with a high number of ly-ext foci (ly-ext high) and one with a low number of ly-ext foci (ly-ext low). Among the patients with ly-ext, only a high number of ly-ext foci was an independent poor prognostic factor. The 3-year recurrence-free survival (RFS) rate of the ly-ext high group was significantly lower than that of the ly-ext low group (14.7% vs. 50.0%, P < 0.01). Then, we analyzed the immune microenvironment of pT1 lung adenocarcinoma with ly-ext (13 cases of ly-ext high and 11 cases of ly-ext low tumor) by immunohistochemistry using antibodies for stem cell markers (aldehyde dehydrogenase 1 A1 and CD44), tumor-promoting mucin (MUC1), tumor-infiltrating lymphocytes (CD4, CD8, FOXP3, and CD79a), and tumor-associated macrophages (CD204). The number of CD8+ TILs within the primary lesion was significantly lower and the number of FOXP3+ TILs within the primary lesion was significantly higher in the ly-ext high group (P < 0.05 and P < 0.01, respectively). Our results indicated that a high number of ly-ext foci was an independent poor prognostic factor. Moreover, tumors with high numbers of ly-ext foci had a more immunosuppressive microenvironment.

Significance of chemotherapy-free interval and tumor regression grade in patients with recurrent esophageal squamous cell carcinoma receiving chemotherapy with fluorouracil and platinum after esophagectomy following preoperative chemotherapy.

BACKGROUND: In Japan, standard treatment for locally advanced esophageal squamous cell carcinoma (ESCC) includes preoperative chemotherapy with fluorouracil plus cisplatin followed by esophagectomy. However, its efficacy is unclear in patients with recurrent disease with < 6 months of chemotherapy-free interval (CFI) after preoperative chemotherapy followed by esophagectomy and in those with ≥ 6 months of CFI and poor pathological response to prior preoperative chemotherapy. METHOD: We retrospectively evaluated the efficacy of fluorouracil plus platinum in patients with recurrent ESCC who received preoperative chemotherapy followed by curative esophagectomy. RESULTS: Among 105 patients with recurrent ESCC after preoperative chemotherapy followed by esophagectomy, a total of 55 patients received fluorouracil plus platinum for recurrent disease. Patients with a CFI < 6 months (n = 20) had significantly shorter overall survival (OS) (median, 7.1 vs 14.5 months, P = 0.008) compared with those with a CFI ≥ 6 months (n = 35). Multivariate analysis showed that OS was worse in patients with a CFI < 6 months or a tumor regression grade (TRG) ≤ 1a. Furthermore, in patients with a CFI ≥ 6 months, TRG ≤ 1a was associated with significantly shorter OS (11.1 months vs. not reached, P = 0.001). CONCLUSION: Fluorouracil plus platinum was ineffective for recurrent ESCC in patients with a CFI < 6 months and in those with a CFI ≥ 6 months and a TRG ≤ 1a. Alternate regimens including nivolumab or pembrolizumab might be considered for the treatment for recurrence in these patients.

Oxidative stress and Liver X Receptor agonist induce hepatocellular carcinoma in Non-alcoholic steatohepatitis model.

BACKGROUND AND AIM: The incidence of non-alcoholic steatohepatitis (NASH)-related hepatocellular carcinoma (HCC) is progressively increasing. However, the pathophysiology and etiology of NASH progression to HCC are unknown. We hypothesized that steatosis was the key factor in NASH-related hepatocarcinogenesis and aimed to evaluate the effects of long-term liver X receptor (LXR) agonist stimulation on hepatic steatosis induced by a high-fat diet and oxidative stress. METHODS: We used an LXR agonist (T0901317) and CCl4 to induce hepatic steatosis and oxidative stress, respectively. C57BL/6 mice fed with a high-fat diet were treated with either T0901317 + CCl4 (T09 + CCl4 group) or CCl4 alone (CCl4 group). T0901317 (2.5 mg/kg) and CCl4 (0.1 mL/kg) were intraperitoneally administered twice weekly for 24 weeks. RESULTS: The liver-to-body weight ratio was significantly higher in the T09 + CCl4 group than in the CCl4 group. Mice in the T09 + CCl4 group exhibited abnormal lipid metabolism and NASH-like histopathological features. Additionally, all mice in the T09 + CCl4 group developed liver tumors diagnosed as well-differentiated HCC. The genes identified via microarray analysis were related to NASH and HCC development. CONCLUSIONS: By combining long-term LXR agonist stimulation with oxidative stress and a high-fat diet, we successfully reproduced liver conditions in mice similar to those in humans with NASH and progression to HCC. Our results provide new insight into NASH-related HCC progression and therapy.

An autopsy case of aortic dissection due to giant cell arteritis.

Giant cell arteritis (GCA) is a systemic vasculitis affecting mainly large and medium-sized arteries. GCA sometimes involves the aorta and its major branches and causes aortic dissection as a rare complication. We have experienced an autopsy case of aortic dissection due to GCA. The patient was an 87-year-old Japanese woman with Stanford type A aortic dissection who died 7 days after admission. Two years previously she had been diagnosed as having abdominal aortic aneurysm and undergone endovascular aneurysm repair (EVAR). Although she had no characteristic symptoms of GCA, autopsy revealed marked granulomatous inflammation in the dissected area and coronary arteries. Active arteritis was evident not only in the arteries of the upper extremity but also those in the lower extremity. Granulomatous inflammation was not evident in the aneurysm. The aortic dissection might have been an initial manifestation of GCA. We report the regions of GCA extension and its histology in detail.

Urgent Proton Beam Therapy With Interinstitutional Transfer for Patients With Intracranial Rhabdomyosarcoma: Report of 3 Cases.

A number of cases have been reported in recent years regarding the use of proton beam therapy to mitigate adverse events affecting important cranial organs in cases of rhabdomyosarcoma at parameningeal sites. However, few reports have described the use of proton beam therapy as urgent radiotherapy for parameningeal rhabdomyosarcoma with intracranial extension. We treated 3 patients diagnosed with parameningeal rhabdomyosarcoma extending into the cranium who were assessed at other hospitals as suitable for urgent radiotherapy and transferred to our hospital for proton beam therapy. These patients comprised 2 boys and 1 girl 6 to 12 years of age at diagnosis, and proton beam therapy was started on days 5, 11, and 23 after diagnosis, respectively. Patients with parameningeal rhabdomyosarcoma extending into the cranium can be transferred to institutions equipped to perform proton beam therapy. To minimize the interval to starting therapy, medical information should be shared with institutions capable of providing such therapy as soon as the possibility of intracranial soft-tissue sarcoma is recognized. Proton beam therapy is 1 option for radiotherapy in cases of intracranial rhabdomyosarcoma.

SOX2 and PI3K Cooperate to Induce and Stabilize a Squamous-Committed Stem Cell Injury State during Lung Squamous Cell Carcinoma Pathogenesis.

Although cancers are considered stem cell diseases, mechanisms involving stem cell alterations are poorly understood. Squamous cell carcinoma (SQCC) is the second most common lung cancer, and its pathogenesis appears to hinge on changes in the stem cell behavior of basal cells in the bronchial airways. Basal cells are normally quiescent and differentiate into mucociliary epithelia. Smoking triggers a hyperproliferative response resulting in progressive premalignant epithelial changes ranging from squamous metaplasia to dysplasia. These changes can regress naturally, even with chronic smoking. However, for unknown reasons, dysplasias have higher progression rates than earlier stages. We used primary human tracheobronchial basal cells to investigate how copy number gains in SOX2 and PIK3CA at 3q26-28, which co-occur in dysplasia and are observed in 94% of SQCCs, may promote progression. We find that SOX2 cooperates with PI3K signaling, which is activated by smoking, to initiate the squamous injury response in basal cells. This response involves SOX9 repression, and, accordingly, SOX2 and PI3K signaling levels are high during dysplasia, while SOX9 is not expressed. By contrast, during regeneration of mucociliary epithelia, PI3K signaling is low and basal cells transiently enter a SOX2LoSOX9Hi state, with SOX9 promoting proliferation and preventing squamous differentiation. Transient reduction in SOX2 is necessary for ciliogenesis, although SOX2 expression later rises and drives mucinous differentiation, as SOX9 levels decline. Frequent coamplification of SOX2 and PIK3CA in dysplasia may, thus, promote progression by locking basal cells in a SOX2HiSOX9Lo state with active PI3K signaling, which sustains the squamous injury response while precluding normal mucociliary differentiation. Surprisingly, we find that, although later in invasive carcinoma SOX9 is generally expressed at low levels, its expression is higher in a subset of SQCCs with less squamous identity and worse clinical outcome. We propose that early pathogenesis of most SQCCs involves stabilization of the squamous injury state in stem cells through copy number gains at 3q, with the pro-proliferative activity of SOX9 possibly being exploited in a subset of SQCCs in later stages.

Dickkopf-related protein 3 promotes cell adhesion and invasion during progression of lung adenocarcinoma.

Dickkopf-related protein 3 (DKK3) is one of the DKK family (DKK1-4), an evolutionally conserved group of secreted glycoproteins characterized by two distinct cysteine-rich domains. DKK3 is considered to be a tumor suppressor gene. However, it has been shown that 30-50% of various cancers are DKK3-positive, suggesting that DKK3 may have an additional function other than tumor suppression. In this study, we focused on lung adenocarcinoma, which is the major histological type of lung cancer. We analyzed the relationship between DKK3 expression and clinicopathological features by immunohistochemistry, using 200 lung adenocarcinoma specimens. We found that 40.5% and 59.5% of cases were DKK3-positive and -negative, respectively, and that positive cases had a greater tendency for progression than negative cases (P < 0.05). Furthermore, in vitro analyses demonstrated that DKK3 suppression affected cell adhesion in three DKK3-expressing lung adenocarcinoma cell lines and that DKK3-knockdown cells were less invasive in comparison to control cells. These results suggest that DKK3 plays a role in the progression of lung adenocarcinoma by promoting cell adhesion and invasion. DKK3 might be a new extracellular cancer therapeutic target, and it seems important to clarify molecular mechanisms underlying the DKK3 functions depending on cell context.

A case of microscopic, multiple sclerosing pneumocytoma.

Sclerosing pneumocytoma is a rare tumor of the lung, commonly affecting middle-aged women, and is mostly isolated. Although this tumor is thought to be derived from primitive respiratory epithelial cells, the characteristics of the precursor cells are still unknown. A 19-year-old woman presented with multiple nodules in the right lung. Partial resection of the right middle lobe was performed, and seven sclerosing pneumocytomas, including four that were microscopic, were detected. The latter showed a simple papillary pattern, and three of them consisted of only round cell-like cells (single population). Interestingly, these round cell-like cells were positive for both p63 and TTF-1, but totally negative for SP-A. On the other hand, the tumor cells of the other four sclerosing pneumocytomas showing a papillary pattern with a dual population, were diffusely positive for TTF-1 and focally positive for SP-A (only in surface cells), but negative or very focally positive for p63. It has been reported that p63-positive stem cell-like cells are present in the distal airway and have potential to differentiate into type II pneumocytes. The immunohistochemical features of these multiple microscopic lesions suggest that the p63-TTF-1 double-positive cells are candidate precursor cells of sclerosing pneumocytoma.