Prognostic and therapeutic implications of aromatase expression in lung adenocarcinomas with EGFR mutations

New Perspectives on Sex Steroid Hormones Signaling in Cancer-Associated Fibroblasts of Non-Small Cell Lung Cancer

The importance of sex hormones, especially estrogen, in the pathogenesis of non-small-cell lung cancer (NSCLC) has attracted attention due to its high incidence among young adults and nonsmokers, especially those who are female. Cancer-associated fibroblasts (CAFs) reside in the cancer stroma and influence cancer growth, invasion, metastasis, and acquisition of drug resistance through interactions with cancer cells and other microenvironmental components. Hormone-mediated cell-cell interactions are classic cell-cell interactions and well-known phenomena in breast cancer and prostate cancer CAFs. In cancers of other organs, including NSCLC, the effects of CAFs on hormone-receptor expression and hormone production in cancer tissues have been reported; however, there are few such studies. Many more studies have been performed on breast and prostate cancers. Recent advances in technology, particularly single-cell analysis techniques, have led to significant advances in the classification and function of CAFs. However, the importance of sex hormones in cell-cell interactions of CAFs in NSCLC remains unclear. This review summarizes reports on CAFs in NSCLC and sex hormones in cancer and immune cells surrounding CAFs. Furthermore, we discuss the prospects of sex-hormone research involving CAFs in NSCLC.

Relationship between consolidation tumor ratio and tumor-infiltrating lymphocytes in small-sized lung adenocarcinoma

Background

Consolidation tumor ratio (CTR) is associated with cancer progression and histological invasiveness in lung adenocarcinoma (LAD). However, little is known about the association between CTR and immune‐related factors, including tumor‐infiltrating lymphocytes (TILs) density or tumor expression of programmed death ligand 1 (PD‐L1) and indoleamine 2,3‐dioxygenase 1 (IDO1) in small‐sized LAD.

Methods

This study included 258 patients with LAD (<3 cm) who underwent surgery. Patients were assigned to four groups: CTR = 0; 0 < CTR <0.5; 0.5 ≤ CTR <1 (ground‐glass opacity [GGO] group); and CTR = 1 (pure‐solid group). CD4⁺, CD8⁺, and FoxP3⁺ TIL density and PD‐L1 and IDO1 tumor expression were assessed by immunohistochemistry.

Results

Among the GGO group, CD8⁺ and FoxP3⁺ TIL density increased significantly with increasing CTR (p < 0.001 and p < 0.001, respectively). Moreover, PD‐L1 and IDO1 expression was significantly higher in the pure‐solid group than in the GGO group (p < 0.001 and p < 0.001, respectively).

Conclusions

CTR was correlated with the abundance of CD8⁺ and FoxP3⁺ TILs in the GGO group. PD‐L1 and IDO1 positivity rates were significantly higher in the pure‐solid group than in the GGO group. Increased CTR may be correlated with immunosuppressive condition.

Regulation of aromatase in cancer

The regulation of aromatase, an enzyme involved in the biosynthesis of estrogen in normal and cancer cells, has been associated with growth factor signaling and immune response modulation. The tissue-specific regulatory roles of these factors are of particular importance as local aromatase expression is strongly linked to cancer development/progression and disease outcomes in patients. Therefore, aromatase has become a chemotherapeutic target and aromatase inhibitors (AIs) are used in the clinic for treating hormone-dependent cancers. Although AIs have shown promising results in the treatment of cancers, the emerging increase in AI-resistance necessitates the development of new and improved targeted therapies. This review discusses the role of tumor and stromal-derived growth factors and immune cell modulators in regulating aromatase. Current single-agent and combination therapies with or without AIs targeting growth factors and immune checkpoints are also discussed. This review highlights recent studies that show new connections between growth factors, mediators of immune response, and aromatase regulation.

Clinical significance of preoperative inflammatory markers in non-small cell lung cancer patients: A multicenter retrospective study

Inflammatory biomarkers have been associated with clinical outcomes in non-small cell lung cancer (NSCLC). However, the best prognostic marker(s) has not been identified, and the association between inflammatory markers and clinical characteristics is poorly understood. We selected 1,237 patients with resected NSCLC from Kyushu University (2003–2015) and Kyushu Cancer Center (2009–2015) in Japan. Pearson product-moment correlation coefficient among inflammatory markers and area under curve (AUC) of receiver operating characteristic (ROC) curve analyses for overall survival (OS) were calculated. We analyzed the associations between inflammatory markers and clinical factors using Student’s t-test. Univariate and multivariate analyses with Cox proportional hazards regression analyses were performed to evaluate the relationship between survival and clinical factors. The cut-off values for neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), platelet-lymphocyte ratio, and derived NLR (dNLR) were determined by ROC curve analyses for OS. We found a strong positive correlation between NLR and dNLR (r = 0.9629). The AUC of LMR was the highest amongst the measured metrics, and the AUC of NLR was higher than dNLR. Levels of some inflammatory markers were associated with sex, smoking, squamous cell carcinoma, and pathological stage. LMR ≥ 5.11 and lactate dehydrogenase (LDH) concentration ≥ 222 (U/L) were independent predictors of both disease-free survival (DFS) and OS (LMR; P = 0.0009 and 0.0008, LDH; P = 0.0195 and 0.0187, respectively). Certain inflammatory markers, potentially linked to smoking, were associated with an advanced pathological stage in NSCLC. LMR and LDH were independent predictors of both DFS and OS.

LIMD1 Increases the Sensitivity of Lung Adenocarcinoma Cells to Cisplatin via the GADD45α/p38 MAPK Signaling Pathway

Objective: To investigate the effect of LIM domain-containing protein 1 (LIMD1) on the sensitivity of lung adenocarcinoma cells to cisplatin and explore the mechanism.

Methods: A549 and H1299 cells were transfected with lentivirus to establish LIMD1-overexpressing cell lines and their respective controls. The protein expression of DNA damage-inducible 45 alpha (GADD45α) and p38 mitogen-activated protein kinase (MAPK) was detected by Western blot. The survival of A549-vec, A549-LIMD1, H1299-vec, and H1299-LIMD1 cells after cisplatin treatment was observed by CCK-8, and the viability was calculated accordingly. Then, SB203580 was used to inhibit the activity of the p38 MAPK signaling pathway, after which the survival of A549-vec, A549-LIMD1, H1299-vec, and H1299-LIMD1 cells in response to cisplatin was observed again by CCK-8, and the viability was calculated accordingly.

Results: When LIMD1 was overexpressed in A549 and H1299 cells, the levels of GADD45α and p-p38 MAPK were increased, but total p38 MAPK expression showed no significant change. After adding 30 μM cisplatin, the optical density (OD) values of A549-LIMD1 and H1299-LIMD1 cells were significantly lower than those of their respective controls at 24, 48, and 72 h. The viability of A549-LIMD1 and H1299-LIMD1 cells was significantly lower than that of their respective controls at all the times tested (p < 0.05). The Western blot results showed that the expression of apoptotic proteins cleaved caspase 3 and cleaved PARP in cisplatin-treated A549-LIDM1 and H1299-LIMD1 cells was significantly higher than that in their respective control cells. Flow cytometry showed that the apoptosis rates of A549-LIMD1 and H1299-LIMD1 cells were significantly higher than those of their respective controls (p < 0.05). SB203580 significantly inhibited the activation of the p38 MAPK signaling pathway in lung adenocarcinoma cells; however, neither the OD values nor the viability of A549-LIMD1 cells and H1299-LIMD1 cells showed no significant difference from those of their controls at 24, 48, and 72 h after cisplatin and SB203580 treatment (p > 0.05 for both). Western blot analysis showed that after SB203580 was added, the expression of cleaved caspase 3 and cleaved PARP in A549-LIMD1 and H1299-LIMD1 cells presented no significant difference compared with that in their respective controls.

Conclusion: LIMD1 increases the sensitivity of lung adenocarcinoma cells to cisplatin by activating the GADD45α/p38 MAPK signaling pathway.

Radiological Features of Programmed Cell Death-Ligand 2-positive Lung Adenocarcinoma: A Single-institution Retrospective Study

AIM

Programmed cell death-ligand 1 and 2 (PD-L1 and PD-L2) are ligands of the programmed cell death-1 (PD1) receptor. PD1/PD-L1 inhibitors have shown clinical efficacy in non-small cell lung cancer (NSCLC). However, relatively little is known about the expression of PD-L2, or its association with the clinicopathological features of NSCLC. Here, the radiological features of PD-L2-positive lung adenocarcinoma were evaluated.

MATERIALS AND METHODS

PD-L1 and PD-L2 expression were evaluated by immunohistochemical staining of surgically-resected specimens from 393 patients with primary lung adenocarcinoma who underwent preoperative thin-section computed tomography (CT), 222 of whom also underwent ¹⁸F-fluorodeoxyglucose positron-emission tomography/CT (¹⁸F-FDG-PET/CT).

RESULTS

Among the 393 specimens, 132 (33.6%) and 266 (67.7%) were positive for PD-L1 and PD-L2 expression, respectively. Multivariate analysis showed that the absence of surrounding ground glass opacity and the presence of air bronchogram were significantly associated with PD-L2 expression; however, there was no significant association between PD-L2 expression and the consolidation/tumor ratio. In 222 ¹⁸F-FDG-PET/CT, the maximum standardized uptake value was significantly higher in patients with PD-L2-positive compared to those with PD-L2-negative tumors.

CONCLUSION

PD-L2-positive lung adenocarcinomas are less radiologically malignant and invasive than their PD-L1-positive counterparts.

A Positive Correlation Between the EZH2 and PD-L1 Expression in Resected Lung Adenocarcinomas

BACKGROUND

Enhancer of zeste homolog 2 (EZH2) is reported to be involved in lung cancer pathogenesis via the epigenetic regulation of various genes. Recently, EZH2 was shown to control mechanisms of adaptive resistance to immunotherapy in melanoma; however, the association between EZH2 and programmed death-ligand 1 (PD-L1), which reflects the tumor microenvironment, remains poorly understood.

METHODS

A total of 428 patients with resected lung adenocarcinoma were analyzed for their EZH2 and PD-L1 expression by immunohistochemistry and evaluated to determine the association between the EZH2 and PD-L1 expression.

RESULTS

Among 428 patients, the EZH2 expression was identified in 219 (51.2%) patients, while the PD-L1 expression was observed in 88 (20.6%) patients. The recurrence-free and overall survival were significantly shorter in patients with the EZH2 expression than in those without it. A multivariate analysis showed that EZH2 remained an independent prognosticator for recurrence-free and overall survival. Patients with the EZH2-positive lung adenocarcinoma exhibited a significantly higher expression of PD-L1 than did those without it. A logistic regression analysis with backward elimination revealed that the presence of lymphatic and vessel invasion and PD-L1 positivity were independently associated with the EZH2 expression, while age over 70 years, the presence of vessel invasion, wild-type epidermal growth factor receptor, and EZH2 positivity were significantly associated with the PD-L1 expression.

CONCLUSIONS

EZH2-expressing lung adenocarcinomas were shown to express the PD-L1 protein more frequently than were nonexpressing lesions. This study provides the first evidence of a possible association between the EZH2 and PD-L1 expression in patients with resected lung adenocarcinoma.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Significance of spread through air spaces in early-stage lung adenocarcinomas undergoing limited resection

Background

In early‐stage lung adenocarcinomas, spread through air spaces (STAS) are reported to be a prognostic factor in patients who have undergone sublobar resection, but not lobectomy. In contrast, reports have also shown that STAS is significantly associated with poor survival outcomes after lobectomy, but not after limited resection. Thus, the prognostic impact of STAS differs according to published reports.

Methods

A total of 82 patients with early‐stage adenocarcinomas who underwent limited resection and whose STAS status could be examined were enrolled in this retrospective study. We evaluated the association between STAS and clinicopathological characteristics and postoperative survival.

Results

Among 82 patients, 31 (37.8%) were positive for STAS, while 51 (62.2%) were negative. STAS was significantly associated with advanced tumor stage (P < 0.01), lower histological differentiation (P = 0.01), and the presence of pleural invasion (P = 0.01). Patients with STAS had significantly shorter recurrence‐free survival (RFS) and overall survival (OS) than those without STAS (P < 0.01 and P = 0.02, respectively). According to multivariate analysis, positivity for STAS was an independent prognostic parameter for RFS (P < 0.01), but not OS (P = 0.45). Three patients who developed surgical margin recurrence and one patient who developed distant recurrence were all positive for STAS.

Conclusions

STAS was predictive of poor postoperative survival in patients with early‐stage adenocarcinomas treated with limited resection and was associated with surgical margin recurrence.

Indoleamine 2,3-dioxygenase 1 and programmed cell death-ligand 1 co-expression correlates with aggressive features in lung adenocarcinoma

BACKGROUND

Indoleamine 2,3-dioxygenase 1 (IDO1) is an immunosuppressive effector, and its expression is associated with prognosis in several cancer types. Here, we investigated the relationship between IDO1 expression in lung adenocarcinoma and patient prognosis and clinicopathological features, including programmed cell death-ligand 1 (PD-L1) expression.

MATERIALS AND METHODS

In this study, surgically resected primary lung adenocarcinoma specimens from 427 patients were evaluated for IDO1 and PD-L1 expression by immunohistochemistry, and lung adenocarcinoma cell lines were evaluated for IDO1 and PD-L1 protein expression by enzyme-linked immunosorbent assay and flow cytometry and for messenger RNA levels by real-time reverse-transcriptase polymerase chain reaction analysis.

RESULTS

IDO1 was expressed in 260 patients (60.9%) at 1% cut-off and 63 patients (14.8%) at 50% cut-off. Tissues from 145 patients (34.0%) were positive for PD-L1 using the cut-off of 1%. Multivariate analysis showed that ≥1% IDO1 positivity was significantly associated with higher tumour grade, vascular invasion and PD-L1 expression. IDO1 and PD-L1 proteins were co-expressed in 123 patients (28.8%), and co-expressing tumours exhibited significantly more malignant traits than those positive for one or neither protein. In multivariate analysis, co-expression of IDO1 and PD-L1 was significantly associated with shorter disease-free survival and overall survival. Both proteins were upregulated in lung adenocarcinoma cell lines by treatment with interferon-γ and transforming growth factor-β.

CONCLUSION

These results suggest that IDO1 and PD-L1 co-expression may define an aggressive form of lung adenocarcinoma.

Significance of Spread Through Air Spaces in Resected Lung Adenocarcinomas With Lymph Node Metastasis

BACKGROUND

Spread through air spaces (STAS) is a recently recognized invasive pattern of lung cancer defined by the World Health Organization as micropapillary clusters, solid nests, or single cells spreading within air spaces beyond the edge of the main tumor. Although STAS has been shown to be a significant prognosticator for the postoperative survival in early-stage lung cancer treated with limited resection, its prognostic impact on the survival in completely resected adenocarcinomas with lymph node metastasis remains unclear.

PATIENTS AND METHODS

STAS was assessed in a total of 63 adenocarcinomas with lymph node metastasis in patients who underwent complete resection. STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. We evaluated the association between STAS and the clinicopathologic characteristics and the postoperative survival.

RESULTS

Among 63 patients, 31 (49.2%) and 32 (50.8%) had disease that was pathologically positive for N1 and N2, respectively. STAS was observed in 45 patients (73.0%) and was not significantly associated with any clinicopathologic characteristics. Patients with the STAS had significantly shorter recurrence-free survival (RFS) but not overall survival than those without STAS (P = .04 and P = .35, respectively). The 5-year RFS in patients with and without STAS was 25.1% and 56.7%, respectively. According to a multivariate analysis, positivity for STAS remained an independent prognostic parameter for RFS (hazard ratio = 3.09; 95% confidence interval, 1.47-7.16; P < .01).

CONCLUSION

STAS was predictive of a poor RFS in completely resected adenocarcinomas with lymph node metastasis.

Prediction of potential drivers connecting different dysfunctional levels in lung adenocarcinoma via a protein-protein interaction network

Lung cancer is a serious disease that threatens an affected individual's life. Its pathogenesis has not yet to be fully described, thereby impeding the development of effective treatments and preventive measures. "Cancer driver" theory considers that tumor initiation can be associated with a number of specific mutations in genes called cancer driver genes. Four omics levels, namely, (1) methylation, (2) microRNA, (3) mutation, and (4) mRNA levels, are utilized to cluster cancer driver genes. In this study, the known dysfunctional genes of these four levels were used to identify novel driver genes of lung adenocarcinoma, a subtype of lung cancer. These genes could contribute to the initiation and progression of lung adenocarcinoma in at least two levels. First, random walk with restart algorithm was performed on a protein-protein interaction (PPI) network constructed with PPI information in STRING by using known dysfunctional genes as seed nodes for each level, thereby yielding four groups of possible genes. Second, these genes were further evaluated in a test strategy to exclude false positives and select the most important ones. Finally, after conducting an intersection operation in any two groups of genes, we obtained several inferred driver genes that contributed to the initiation of lung adenocarcinoma in at least two omics levels. Several genes from these groups could be confirmed according to recently published studies. The inferred genes reported in this study were also different from those described in a previous study, suggesting that they can be used as essential supplementary data for investigations on the initiation of lung adenocarcinoma. This article is part of a Special Issue entitled: Accelerating Precision Medicine through Genetic and Genomic Big Data Analysis edited by Yudong Cai & Tao Huang.

Metabolic characteristics of programmed cell death-ligand 1-expressing lung cancer on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography

Programmed cell death‐1 (PD‐1) and programmed cell death‐ligand 1 (PD‐L1) have been identified as novel targets of immunotherapy of lung cancer. In present study, we evaluated the metabolic characteristics of lung cancer by using ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) with regard to PD‐L1 protein expression. PD‐L1 protein expression was evaluated by immunohistochemistry with the antibody clone SP142 in 579 surgically resected primary lung cancer patients. Cases with less than 5% tumor membrane staining were considered negative. We examined the association between the frequency of PD‐L1 protein expression and the maximum standardized uptake value (SUVmax) in preoperative ¹⁸F‐FDG PET/CT. The cut‐off values for SUVmax were determined by receiver operating characteristic curve analyses. The SUVmax was significantly higher in nonsmall cell lung cancer (NSCLC) patients with PD‐L1 protein expression compared with those without PD‐L1 protein expression (P < 0.0001). However, there was no correlation between SUVmax and PD‐L1 protein expression in patients with neuroendocrine tumors (P = 0.6545). Multivariate analysis revealed that smoking, the presence of pleural invasion, and high SUVmax were independent predictors of PD‐L1 positivity. PD‐L1‐expressing NSCLC had a high glucose metabolism. The SUVmax in preoperative ¹⁸F‐FDG PET/CT was a predictor of PD‐L1 protein expression in patients with NSCLC.

Clinical implications of the novel cytokine IL-38 expressed in lung adenocarcinoma: Possible association with PD-L1 expression

Interleukin (IL)-38, a novel member of the IL-1 cytokine family, is homologous to IL-1 receptor antagonist (IL-1Ra) and IL-36Ra, and has been reported to act as an antagonist. IL-38 expression is found in tonsil, placenta, and spleen, and recent studies suggest an association between IL-38 and autoimmune diseases. However, whether IL-38 plays a role in carcinogenesis or cancer growth is unclear. In the present study, we identified increases in IL-38 expression by immunohistochemistry in multiple types of cancer cells. In the examination of 417 surgically resected primary lung adenocarcinomas, Fisher's exact tests showed significant associations between high IL-38 expression and high tumor grades, an advanced T status, advanced N status, advanced stage, and the presence of pleural and vessel invasions. Survival analyses by the Kaplan-Meier method showed that patients with high expression of IL-38 had significantly shorter disease-free survival and shorter overall survival after surgery than patients with low expression of IL-38 (log-rank test: P = 0.0021 and P = 0.0035, respectively). Moreover, programmed cell death-ligand 1 (PD-L1)-positive cases showed higher expression of IL-38 than PD-L1-negative cases (Wilcoxon rank-sum test: P < 0.0001). In conclusion, IL-38 was expressed in tumor cells of various cancers, and IL-38 expression was associated with poor survival of lung adenocarcinoma patients. IL-38 may affect host immunity or the tumor microenvironment, and contribute to the progression of lung adenocarcinoma.

[Recent Advances in Association of Estrogen and Non-small Cell Lung Cancer]

肺癌是目前发病率及死亡率最高的恶性肿瘤之一，其中约85%为非小细胞肺癌（non-small cell lung cancer, NSCLC）。尽管其治疗手段不断提高，但总体预后不容乐观。既往研究已证实雌激素系统参与了NSCLC的发生、发展。越来越多的证据表明，抗雌激素治疗不仅可以逆转NSCLC患者对铂类化疗药物的耐药性，还可以增加人类表皮生长因子受体酪氨酸激酶抑制剂的疗效。本文就雌激素系统及抗雌激素治疗在NSCLC中的作用作一综述。

Exon 7 splicing variant of estrogen receptor α is associated with pathological invasiveness in smoking-independent lung adenocarcinoma

Patients with smoking-independent lung cancer mainly consist of females, yet the molecular background of this epidemiological feature, other than epidermal growth factor receptor (EGFR) mutation, remains unclear. Several studies have revealed the association between female hormone-associated factors and the prognosis of lung cancer, however the data remain inconsistent. The present study focused on the expression of estrogen receptor (ER)α in order to elucidate this association in smoking-independent lung cancer. Immunohistochemistry staining (IHC) of aromatase, ERα and ERβ was performed against formalin-treated tissues from 38 patients who had never-smoked who underwent complete surgical resection between 2012 and 2013. Among them, adequate RNA of the tumor and adjacent normal lung cancer was extracted from 31 matching deep frozen samples. Considering the IHC results, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to measure the expression level of 2 different exons of ERα, exon 6 and exon 7, which are part of the ligand binding domain of ERα, using the Taqman gene expression assay. Extra-nuclear expression of ERα using IHC demonstrated a statistically significant association with pathological invasiveness. RT-qPCR results exhibited a decreased expression of ERα exon 7 in invasive tumor tissues, compared with their adjacent normal tissues. This is consistent with the findings of previous in vitro studies indicating that extra-nuclear ERα were exon 7 splicing variants. No difference was observed in ERα exon 7 expression between normal and tumor tissues in non-invasive lung cancer tissues. When considering the EGFR mutation status, EGFR wild-type lung cancers exhibited decreased ERα exon 7 expression levels compared with EGFR mutated lung cancers. Extra-nuclear expression of ERα, which may represent exon 7 splicing variants of ERα, showed statistical association with pathological invasiveness in smoking-independent lung cancer. The post-translational splicing mechanism of ERα may be involved in the acquired invasiveness of smoking independent lung cancer.

Relevance Between Programmed Death Ligand 1 and Radiologic Invasiveness in Pathologic Stage I Lung Adenocarcinoma

BACKGROUND

Programmed death ligand 1 (PD-L1) was reported to predict the response of immunotherapy; however, the association between PD-L1 expression and radiologic and pathologic features has yet to be elucidated.

METHODS

In all, 292 patients with resected pathologic stage I adenocarcinoma were analyzed for PD-L1 expression by immunohistochemistry and evaluated to determine the association between PD-L1 expression and the radiologic/pathologic invasiveness. Specifically, the radiologic invasiveness and noninvasiveness were determined based on the consolidation/tumor ratio, with a cutoff value of 0.25 by thin-section computed tomography.

RESULTS

Among 292 patients, 47 (16.1%) were positive for PD-L1 expression; the remaining 245 patients (83.9%) were negative for PD-L1 expression. Fisher's exact test demonstrated that PD-L1 expression was significantly associated with a higher consolidation/tumor ratio (p = 0.029) and higher maximum standardized uptake value (p = 0.004). The mean values of consolidation/tumor ratio and maximum standardized uptake in patients with and without PD-L1 expression were 0.845 ± 0.052 and 7.241 ± 0.795, and 0.607 ± 0.023 and 3.60 ± 0.364, respectively (p < 0.001 and p < 0.001, respectively). Among 47 adenocarcinomas harboring PD-L1 expression, the frequencies of PD-L1 expression for consolidation/tumor ratios of 0, 0.1 to 0.25, 0.26 to 0.5, and 0.51 or more were 6.4%, 2.1%, 4.3%, and 87.2%, respectively (p = 0.007). Pathologically, PD-L1 was identified exclusively only in more invasive subtypes, not in less invasive ones, such as atypical adenomatous hyperplasia, adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant ones (p < 0.001).

CONCLUSIONS

Expression of PD-L1 was significantly associated with radiologic/pathologic invasive adenocarcinomas. This study provides the first evidence of the radiologic and pathologic invasiveness in resected pathologic stage I adenocarcinoma with PD-L1 expression.

A Comprehensive Analysis of Programmed Cell Death Ligand-1 Expression With the Clone SP142 Antibody in Non-Small-Cell Lung Cancer Patients

BACKGROUND

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with anti-PD-1 therapy currently the standard treatment for non-small-cell lung cancer (NSCLC) patients after the failure of first-line chemotherapy treatment. The recent phase II POPLAR and phase III OAK studies showed that atezolizumab, a representative PD-L1 inhibitor, exhibited a survival benefit compared with standard therapy in patients with NSCLC.

PATIENTS AND METHODS

We examined PD-L1 expression in NSCLC using the clone SP142 of POPLAR and OAK studies. PD-L1 expression in 499 surgically resected NSCLC patients was evaluated using immunohistochemistry using SP142. We set cutoff values as 1%, 5%, 10%, and 50%.

RESULTS

The samples from 189 (37.9%), 119 (23.8%), 71 (14.2%), and 39 (7.8%) patients were positive for PD-L1 expression at cutoff values of 1%, 5%, 10%, and 50%, respectively. Fisher exact tests showed that PD-L1 positivity was significantly associated with male sex, smoking, advanced stage, the presence of vascular invasion, squamous cell carcinoma, and wild type epidermal growth factor receptor gene mutation status at all cutoff values. Univariate and multivariate survival analyses revealed that PD-L1-positive patients had a worse prognosis than PD-L1-negative patients only at the 1% cutoff value. Forest plot analyses showed that the 1% cutoff provided a more sensitive value for the prediction of postoperative prognosis.

CONCLUSION

PD-L1 expression varied greatly according to different cutoff values. This study might be a useful reference to understand the results of POPLAR and OAK studies and to select patients likely to benefit from atezolizumab.

High Frequency of Programmed Death-ligand 1 Expression in Emphysematous Bullae-associated Lung Adenocarcinomas

OBJECTIVE

Emphysematous bullae (EB) are known to be associated with a high incidence of lung cancer; however, the reason for this has yet to be elucidated. The objective of the present study was to clarify the prevalence of programmed death-ligand-1 (PD-L1) expression in EB-associated lung adenocarcinomas.

PATIENTS AND METHODS

A total of 369 patients with resected lung adenocarcinoma whose preoperative computed tomography findings were available for the examination of EB were analyzed for PD-L1 expression by immunohistochemistry and evaluated to determine the association between PD-L1 expression and EB-related adenocarcinomas.

RESULTS

Among 369 patients, EB and cancer adjoining EB (Ca-ADJ) were identified in 81 (22.0%) and 50 (13.6%) patients, respectively. EB and Ca-ADJ were significantly associated with male gender, a smoking habit, a decreased forced expiratory volume in 1 second, a relatively higher tumor grade, advanced T status and stage, the presence of pleural and vessel invasion, invasive pathologic subtypes, and wild-type epidermal growth factor receptor. Seventy patients (19.0%) were positive for PD-L1 expression, whereas the remaining 299 patients (81.0%) were negative. Thirty-six (44.4%) and 29 (58.0%) of 81 and 50 patients with EB and Ca-ADJ, respectively, were positive for PD-L1 expression, which was shown to be significant by the Fisher exact test (P < .001 and P < .001, respectively). Among the 81 lung adenocarcinomas with EB, Ca-ADJ was significantly associated with PD-L1 expression (P = .021). In a multivariate analysis, the presence of Ca-ADJ was found to be an independent predictor of PD-L1 expression.

CONCLUSIONS

EB-associated lung adenocarcinomas express PD-L1 protein more frequently than those without EB.

Clinical outcome and expression of mutant P53, P16, and Smad4 in lung adenocarcinoma: a prospective study

BACKGROUND

Whole-exome sequencing has shown that lung adenocarcinoma (LAC) can be driven by mutant genes, including TP53, P16, and Smad4. The aim of this study was to clarify protein alterations of P53, P16, and Smad4 and to explore their correlations between the protein alterations and clinical outcome.

METHODS

We investigated associations among P53 mutant (P53(Mut)) expression, and P16 and Smad4 loss-of-expression, with clinical outcome in 120 LAC patients who underwent curative resection, using immunohistochemical (IHC) methods.

RESULTS

Of the 120 patients, 76 (63.3%) expressed P53(Mut) protein, whereas 54 (45.0%) loss of P16 expressed and 75 (62.5%) loss of Smad4 expressed. P53(Mut) expression was associated with tumor size (P = 0.041) and pathological stage (P = 0.025). Loss of P16 expression was associated with lymph node metastasis (P = 0.001) and pathological stage (P < 0.001). Loss of Smad4 expression was associated with tumor size (P = 0.033), lymph node metastasis (P = 0.014), pathological stage (P = 0.017), and tumor differentiation (P = 0.022). Kaplan-Meier survival analysis showed that tumor size (P = 0.031), lymph node metastasis (P < 0.001), pathological stage (P < 0.001), P53(Mut) protein expression (P = 0.038), and loss of p16 or Smad4 expression (P < 0.001) were significantly associated with shorter overall survival(OS), whereas multivariate analysis indicated that lymph node metastasis (P = 0.014) and loss of p16 or Smad4 expression (P < 0.001) were independent prognostic factors. Analysis of protein combinations showed patients with more alterations had poorer survival (P < 0.001). Spearman correlation analysis showed that loss of Smad4 expression inversely correlated with expression of P53(Mut) (r = (-)0.196, P = 0.032) and positively with lost P16 expression (r =0.182, P = 0.047).

CONCLUSIONS

The findings indicate that IHC status of P53(Mut), P16, and Smad4 may predict patient outcomes in LAC.

Preclinical pharmacological evaluation of letrozole as a novel treatment for gliomas

We present data that letrozole, an extensively used aromatase inhibitor in the treatment of estrogen receptor-positive breast tumors in postmenopausal women, may be potentially used in the treatment of glioblastomas. First, we measured the in vitro cytotoxicity of letrozole and aromatase (CYP19A1) expression and activity in human LN229, T98G, U373MG, U251MG, and U87MG, and rat C6 glioma cell lines. Estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 cells served as controls. Cytotoxicity was determined employing the MTT assay, and aromatase activity using an immunoassay that measures the conversion of testosterone to estrogen. Second, in vivo activity of letrozole was assessed in Sprague-Dawley rats orthotopically implanted with C6 gliomas. The changes in tumor volume with letrozole treatment (4 mg/kg/day) were assessed employing μPET/CT imaging, employing [(18)F]-fluorodeoxyglucose (F18-FDG) as the radiotracer. Brain tissues were collected for histologic evaluations. All glioma cell lines included here expressed CYP19A1 and letrozole exerted considerable cytotoxicity and decrease in aromatase activity against these cells (IC50, 0.1-3.5 μmol/L). Imaging analysis employing F18-FDG μPET/CT demonstrated a marked reduction of active tumor volume (>75%) after 8 days of letrozole treatment. Immunohistochemical analysis revealed marked reduction in aromatase expression in tumoral regions of the brain after letrozole treatment. Thus, employing multifaceted tools, we demonstrate that aromatase may be a novel target for the treatment of gliomas and that letrozole, an FDA-approved drug with an outstanding record of safety may be repurposed for the treatment of such primary brain tumors, which currently have few therapeutic options.

[Clinical significance of mutant p53 protein expression in lung adenocarcinoma]

背景与目的

突变型TP53基因不仅丧失了抑癌功能，其编码的突变型P53蛋白还能获得促进细胞增殖、抑制细胞凋亡等功能。目前TP53基因在肺腺癌中突变的临床意义尚不十分明确。本研究旨在探讨突变型P53蛋白在肺腺癌组织中的表达及其临床意义。

方法

回顾性分析120例肺腺癌手术患者的临床病理资料，应用免疫组化法检测患者组织标本中突变型P53蛋白的表达，采用χ²检验分析突变型P53蛋白表达与各临床病理参数的关系，采用单因素生存分析及多因素生存分析法分析突变型P53蛋白表达与总生存期的关系。

结果

突变型P53蛋白在肺腺癌组织中的表达率为63.7%，突变型P53蛋白的表达与肿瘤大小（P=0.041）及病理分期（P=0.025）有关。单因素生存分析提示肿瘤大小（P=0.031）、淋巴结转移（P < 0.001）、病理分期（P < 0.001）以及突变型P53蛋白的表达（P=0.038）与患者总生存期密切相关。多因素生存分析提示仅有淋巴结转移（P=0.014）是患者总生存期的独立影响因素。

结论

TP53基因突变的肺腺癌患者预后较差，突变型P53蛋白可以作为预测患者预后的分子标志物。