Comprehensive analysis of the clinicopathological features, targetable profile, and prognosis of mucinous adenocarcinoma of the lung

Prognostic factors for invasive mucinous adenocarcinoma of the lung: systematic review and meta-analysis

BACKGROUND

Invasive mucinous adenocarcinoma of the lung (IMA) is a unique and rare subtype of lung adenocarcinoma with poorly defined prognostic factors and highly controversial studies. Hence, this study aimed to comprehensively identify and summarize the prognostic factors associated with IMA.

METHODS

A comprehensive search of relevant literature was conducted in the PubMed, Embase, Cochrane, and Web of Science databases from their inception until June 2023. The pooled hazard ratio (HR) and corresponding 95% confidence intervals (CI) of overall survival (OS) and/or disease-free survival (DFS) were obtained to evaluate potential prognostic factors.

RESULTS

A total of 1062 patients from 11 studies were included. In univariate analysis, we found that gender, age, TNM stage, smoking history, lymph node metastasis, pleural metastasis, spread through air spaces (STAS), tumor size, pathological grade, computed tomography (CT) findings of consolidative-type morphology, pneumonia type, and well-defined heterogeneous ground-glass opacity (GGO) were risk factors for IMA, and spiculated margin sign was a protective factor. In multivariate analysis, smoking history, lymph node metastasis, pathological grade, STAS, tumor size, and pneumonia type sign were found to be risk factors. There was not enough evidence that epidermal growth factor receptor (EGFR) mutations, anaplastic lymphoma kinase (ALK) mutations, CT signs of lobulated margin, and air bronchogram were related to the prognosis for IMA.

CONCLUSION

In this study, we comprehensively analyzed prognostic factors for invasive mucinous adenocarcinoma of the lung in univariate and multivariate analyses of OS and/or DFS. Finally, 12 risk factors and 1 protective factor were identified. These findings may help guide the clinical management of patients with invasive mucinous adenocarcinoma of the lung.

Systemic immune-inflammation index predicts survival in patients with resected lung invasive mucinous adenocarcinoma

BACKGROUND

The prognostic-related factors of lung invasive mucinous adenocarcinoma(IMA) are unclear because of its rarity. Various inflammation-based biomarkers were reported to predict the survival of malignant diseases. This study aims to explore the prognostic significance of the systemic immune-inflammation index(SII), which is calculated using absolute platelet, neutrophil, and lymphocyte counts, among patients with invasive mucinous adenocarcinoma.

METHODS

From January 2015 to December 2019, 106 patients were identified as having IMA accepted radical resection and enrolled in the retrospective study. We analyzed the overall survival and disease-free survival using the Kaplan-Meier method and log-rank test. Receiver operating characteristic curve was used to find the optimal SII cut-off values for survival. A Cox regression model was carried out for multivariable analyses.

RESULTS

The study cohort included 53 men and 53 women, with a mean age of 60 years (range 29 to 78 years, median 61 years). The median SII measured before surgery was 378.47 (range: 79.87-1701.97). ROC analyses revealed that the optimal cut-off values of SII was 379.43 for predicting both OS and DFS. An elevated SII (≥379.43) was observed in 52 patients (49.1 %), and was associated with younger age (P = 0.02), advanced T staging (P = 0.042), lymph node metastasis (P = 0.018) and pneumonic-type IMA (P = 0.018). Multivariable analysis showed that SII and pneumonic-type IMA were independent prognostic predictors of OS and DFS in radically resected IMA patients (P < 0.05).

CONCLUSION

High SII is correlated with worse outcome and can be a novel prognostic biomarker for IMA patients accepted radical surgery.

Pulmonary invasive mucinous adenocarcinoma

Invasive mucinous adenocarcinoma (IMA) is a relatively rare subtype of lung adenocarcinoma, composed of goblet and/or columnar tumour cells containing abundant intracytoplasmic mucin vacuoles. While a majority of IMAs are driven by KRAS mutations, recent studies have identified distinct genomic alterations, such as NRG1 and ERBB2 fusions. IMAs also more frequently present as a pneumonic-like pattern with multifocal and multilobar involvement, and comparative genomic profiling predominantly shows a clonal relationship, suggesting intrapulmonary metastases rather than synchronous primary tumours. Accordingly, these unique features require different therapeutic approaches when compared to nonmucinous adenocarcinomas in general. In this article, we review recent updates on the histopathological, clinical, and molecular features of IMAs, and also highlight some unresolved issues for future studies.

Diagnostic gastrointestinal markers in primary lung cancer and pulmonary metastases

Histopathological diagnosis of pulmonary tumors is essential for treatment decisions. The distinction between primary lung adenocarcinoma and pulmonary metastasis from the gastrointestinal (GI) tract may be difficult. Therefore, we compared the diagnostic value of several immunohistochemical markers in pulmonary tumors. Tissue microarrays from 629 resected primary lung cancers and 422 resected pulmonary epithelial metastases from various sites (whereof 275 colorectal cancer) were investigated for the immunohistochemical expression of CDH17, GPA33, MUC2, MUC6, SATB2, and SMAD4, for comparison with CDX2, CK20, CK7, and TTF-1. The most sensitive markers for GI origin were GPA33 (positive in 98%, 60%, and 100% of pulmonary metastases from colorectal cancer, pancreatic cancer, and other GI adenocarcinomas, respectively), CDX2 (99/40/100%), and CDH17 (99/0/100%). In comparison, SATB2 and CK20 showed higher specificity, with expression in 5% and 10% of mucinous primary lung adenocarcinomas and both in 0% of TTF-1-negative non-mucinous primary lung adenocarcinomas (25-50% and 5-16%, respectively, for GPA33/CDX2/CDH17). MUC2 was negative in all primary lung cancers, but positive only in less than half of pulmonary metastases from mucinous adenocarcinomas from other organs. Combining six GI markers did not perfectly separate primary lung cancers from pulmonary metastases including subgroups such as mucinous adenocarcinomas or CK7-positive GI tract metastases. This comprehensive comparison suggests that CDH17, GPA33, and SATB2 may be used as equivalent alternatives to CDX2 and CK20. However, no single or combination of markers can categorically distinguish primary lung cancers from metastatic GI tract cancer.

Molecular insight of p53/Sp1/MUC5AC axis in the tumorigenesis and progression of lung adenocarcinoma

The aberrant expression of secretory mucin MUC5AC has been documented during the tumourigenesis and progression of various cancers. However, little is currently known on the function of MUC5AC in lung adenocarcinoma. The present study focused on the tumour-promoting role of MUC5AC and its regulatory mechanisms in lung adenocarcinoma. Firstly, MUC5AC expression was evaluated in NSCLC tissue microarrays by immunohistochemistry. Kaplan-Meier analysis were used to clarify the prognostic value of MUC5AC. Subsequently, small interfering RNA and small hairpin RNA were used to knockdown MUC5AC in lung ADC cell lines to elucidate its role in tumorigenesis and progression of lung adenocarcinoma via in vitro functional assays and xenograft mouse models. Finally, the regulatory mechanisms underlying p53/Sp1/MUC5AC axis were identified through dual-luciferase report. We found that MUC5AC was upregulated in lung ADC tissues and cell lines, especially in KRAS-mutant cases and correlated with poor prognosis. MUC5AC gene silencing resulted in reduced cell proliferation, invasion and migration. Furthermore, knockdown of MUC5AC led to reversion of the epithelial-mesenchymal transition. Additionally, downregulation of MUC5AC reduced tumourigenesis in mouse models. Finally, we found an antagonistic role between Sp1 and p53 in the regulation of MUC5AC gene expression. Our findings suggest that high MUC5AC expression promotes tumourigenesis and progression of lung ADC. Both p53 gene inactivation and Sp1 overexpression in lung ADC may enhance MUC5AC expression, especially in KRAS-mutated cases. Given the paucity of efficient drug-targeted approaches of KRAS-driven lung ADCs, therapies directed at downstream effectors such as MUC5AC could have huge prospects.

Association of thyroid transcription factor-1 with the efficacy of immune-checkpoint inhibitors in patients with advanced lung adenocarcinoma

Background

We aimed to identify the relationship between thyroid transcription factor‐1 (TTF‐1) expression of lung adenocarcinoma and the efficacy of immune‐checkpoint inhibitor (ICI) therapy.

Methods

This retrospective multicenter study comprised patients with advanced lung adenocarcinoma treated with ICI monotherapy. We collected clinical medical records including data on TTF‐1 expression and analyzed the relationship between TTF‐1 expression and programmed death‐ligand 1 tumor proportion score (PD‐L1 TPS), objective response rate (ORR), progression‐free survival (PFS), and overall survival (OS).

Results

In total, 108 patients with lung adenocarcinoma were analyzed. The rate of TPS ≥1% and ≥50% in patients with positive TTF‐1 expression was significantly higher than that in patients with negative TTF‐1 expression (88% vs. 60%, p < 0.001; 65% vs. 24%, p < 0.001). The ORR was significantly higher in TTF‐1 positive patients than in TTF‐1‐negative patients (38% vs. 8%, p = 0.003). Among patients with TPS ≥50% and 1%–49%, the ORR in TTF‐1 positive and negative patients was 48% (26/54) versus 17% (1/6) (p = 0.21), and 32% (6/19) versus 11% (1/9) (p = 0.37), respectively. The ORR for patients with TPS <1% was 0% in both the TTF‐1 negative and positive cases. The median PFS and OS was significantly longer in TTF‐1‐positive patients than in TTF‐1‐negative patients (5.4 vs. 1.6 months, p < 0.001; 18.2 vs. 8.0 months, p = 0.041). Multivariate analysis revealed that TTF‐1‐negative status was an independent unfavorable prognostic factor for PFS.

Conclusion

Patients with TTF‐1‐positive status receiving ICI monotherapy showed better outcomes than those with TTF‐1‐negative lung adenocarcinoma.

Clinicopathological features of pulmonary mucinous adenocarcinoma: A descriptive analysis

BACKGROUND

Mucinous adenocarcinoma is a rare subtype of lung cancer characterized by abnormal mucin production. We sought to investigate the clinical and pathological features of pulmonary mucinous adenocarcinomas and to identify prognostic factors.

METHODS

This was a single-institution retrospective review of patients with pulmonary mucinous adenocarcinoma diagnosed between January 1, 2015 and December 31, 2020. Descriptive analysis included demographics, diagnostic data, and treatment modalities. The primary outcome was overall survival (OS).

RESULTS

Fifty-six patients were included in the study. Median age was 65 years (range: 26-84), 30 (54%) were female, 48 (86%) had a smoking history, and 41 (73%) patients had ECOG performance status 0-1. Nearly half (26, 46%) were stage IV at presentation, while 11 (20%) presented as stage I, 10 (18%) stage II, and 9 (16%) stage III. Biomarker testing increased through the study period. Where performed, 4/48 (8%) cases were ALK positive, but there were no EGFR cases identified (0/36). Only 3/20 cases had PD-L1 expression >50%. Curative intent therapy was performed in 23 patients (17 had surgery +/- chemotherapy/radiation, 4 had radiotherapy alone, 2 had chemoradiation). Median OS in the entire population was 16.1 months (m). OS by stage was 50.0m for stage I, not reached for stage II, 20.7m for stage III, and 8.1m for stage IV.

CONCLUSIONS

The overall prognosis of pulmonary mucinous adenocarcinoma appears similar to that of non-mucinous adenocarcinomas, with distinct differences noted in the incidence of oncogenic driver mutations, particularly an absence of EGFR mutations.