Targeted sequencing may facilitate differential diagnostics of pulmonary tumours: a case series

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.

Successful therapy using high-dose furmonertinib for non-small cell lung cancer with leptomeningeal metastasis: a case report and literature review

Background

Lung cancer is the second most common form of malignant tumor and has the highest mortality rate worldwide. Among its subtypes, lung adenocarcinoma is the most prevalent. Leptomeningeal metastasis (LM) is rare and is characterized by a dismal prognosis, with overall survival periods typically spanning 4 to 6 weeks without treatment. However, in specific cases, survival can be extended to 4 to 6 months with appropriate therapy. The recent approval of third-generation tyrosine kinase inhibitors (TKIs), such as osimertinib, aumolertinib, and furmonertinib, has introduced promising treatment options for individuals with non-small cell lung cancer (NSCLC) who develop LM after developing resistance to first- and second-generation TKIs. These third-generation TKIs exhibit an enhanced ability to penetrate the blood-brain barrier (BBB), opening up new avenues for managing this challenging condition.

Case summary

We report the case of a 48-year-old Chinese man diagnosed with advanced NSCLC harboring an epidermal growth factor receptor (EGFR) mutation. Following a pulmonary lobectomy and postoperative adjuvant therapy with gefitinib, the patient was diagnosed with LM, which was confirmed by his neurologic symptoms, cerebrospinal fluid cytologic analysis, and cranial enhancement magnetic resonance imaging. Subsequently, he received oral treatment in the form of 160 mg of furmonertinib daily. After 5 days of furmonertinib therapy, the patient recovered from lethargy, with an obvious improvement in cognitive function. Follow-up visits revealed a 6-month survival period following the LM diagnosis. Patients with NSCLC and LM typically present with severe symptoms, and the efficacy of systemic treatment, intrathecal chemotherapy, and radiotherapy remains unsatisfactory. We hope that this specific case provide valuable insights into the management of patients with EGFR mutation-associated NSCLC with LM.

Conclusion

Furmonertinib, a third-generation EGFR TKI with notable BBB penetration, shows promise in LM control and the rapid alleviation of intracranial symptoms. Further investigations into appropriate dosage and toxicity management are imperative.

Genomic and Clinical Significance of Multiple Primary Lung Cancers as Determined by Next-Generation Sequencing

INTRODUCTION

Marked variations in survival rates have brought into question whether standard clinicopathologic classification should be applied to patients presenting with multiple primary lung cancers (MPLCs). This study investigated the genetic profiles of MPLCs in a cohort of patients using next-generation sequencing and correlated results to clinicopathologic data and patient outcome.

METHODS

Patients treated surgically with curative intent for two putative primaries of similar histopathology from January 2000 to December 2019 at St Vincent's Hospital Melbourne. DNA and RNA was extracted from formalin-fixed, paraffin-embedded tumor tissue and sequenced on an Ion Torrent Personal Genome Machine system. Patient outcome was determined by overall survival and disease-free survival.

RESULTS

A total of 40 cases fulfilled the inclusion criteria. Mutational profiling was concordant with clinicopathologic diagnosis in most cases; however, seven cases (17.5%) revealed shared mutations suggesting metastatic disease and this was associated with a substantial reduction in overall survival (p < 0.05).

CONCLUSIONS

Our results suggest that gene sequencing technologies are potentially a more accurate diagnostic and prognostic tool compared with traditional histopathologic evaluation in patients presenting with suspected MPLCs, which could better guide management and predict outcomes.

Adenomyoepithelial tumors of the breast: molecular underpinnings of a rare entity

Adenomyoepitheliomas (AMEs) of the breast are uncommon and span the morphologic spectrum of benign, atypical, in situ, and invasive forms. In exceptionally rare cases, these tumors metastasize to regional lymph nodes or distant sites. In the era of genomic characterization, data is limited regarding AMEs. The aim of this study was to provide insight into the molecular underpinnings of a spectrum of AMEs. Seven cases of AMEs of the breast (benign-1, atypical-2, in situ-1, invasive-3) were identified in our files. The seven samples were interrogated using the Oncomine Comprehensive Assay v3 (ThermoFisher). Two atypical AMEs and the malignant in situ AME harbored the same gain-of-function PIK3CA mutation. The malignant in situ AME also showed EGFR amplification, not described previously. Both a benign AME and a malignant invasive AME shared the same gain-of-function AKT1 variant. The benign AME also showed a GNAS mutation. Moreover, the same gain-of-function HRAS mutation was present in an atypical AME and a malignant invasive AME. We also identified co-occurring HRAS and PIK3CA mutations in an ER-positive atypical AME, which has not been previously described. No fusion drivers were detected. We describe the molecular characteristics of the spectrum of AME tumors of the breast, which harbor alterations in the PI3K/AKT pathway. Our findings are clinically relevant with respect to the current options of targeted therapy in the rare instances where malignant AME tumors of the breast progress.

Immunohistochemical profiles in primary lung cancers and epithelial pulmonary metastases

Correct diagnosis of pulmonary tumors is essential for treatment decision and often relies on immunohistochemical markers. We stained tissue microarrays from resected primary lung cancer (n = 665) and pulmonary metastases (n = 425) for CK7, CK20, CDX2, CK5, p40, p63, TTF-1, napsin A, GATA3, and PAX8 to systematically assess the diagnostic value of these markers. Primary lung adenocarcinomas expressed TTF-1 in 90% and napsin A in 84% of the cases, whereas 10% were positive for p63, 7% for CDX2, 2% for CK20, and 2% for GATA3. Only 68% of the lung adenocarcinomas were positive for CK7, TTF-1, and napsin A and negative for all other markers. Primary lung squamous cell carcinomas expressed CK5, p40, and p63 in 94%-97% of cases, whereas 44% were positive for CK7, 20% for GATA3, 7% for CDX2, and 3% for TTF-1. Rare cases expressed PAX8, CK20, or napsin A. Pulmonary metastases of colorectal cancer were positive for CK20 in 83% and CDX2 in 99% of the cases. Rare cases expressed CK7, p63, or PAX8, whereas 4% expressed TTF-1. Pulmonary metastases of renal cell carcinomas were positive for PAX8 in 74%, napsin A in 7%, and CK7 in 7% of the cases. Pulmonary metastases of breast cancer were positive for GATA3 in 93% and CK7 in 78% of the cases, whereas 15% expressed CK5. Information on expression and patterns of immunohistochemical markers facilitates histopathological diagnostics. Evidently, unusual immune profiles occur and may lead to incorrect diagnosis.

Comparison of Three Different TTF-1 Clones in Resected Primary Lung Cancer and Epithelial Pulmonary Metastases

OBJECTIVES

Immunohistochemical staining against thyroid transcription factor 1 (TTF-1) is often used to distinguish lung adenocarcinoma from squamous cell carcinoma and pulmonary metastasis.

METHODS

TTF-1 expression was examined using the antibody clones 8G7G3/1, SPT24, and SP141 on tissue microarrays from 665 cases of resected lung cancers and 428 pulmonary metastases.

RESULTS

Most lung adenocarcinomas, 89%, 93%, and 93%, were positive with TTF-1 clones 8G7G3/1, SPT24, and SP141, respectively. The corresponding figures for lung squamous cell carcinomas were 0%, 6%, and 8%. In total, five (2%), 19 (7%), and 21 (8%) of the pulmonary metastases from colorectal adenocarcinomas were positive with clones 8G7G3/1, SPT24, and SP141, respectively. Other TTF-1-positive pulmonary metastases (n = 8) were thyroid, urothelial, pancreatic, small bowel, and cervix carcinomas.

CONCLUSIONS

TTF-1 expression in lung cancer and pulmonary metastases differs between clones, with 8G7G3/1 being more specific but less sensitive compared with SPT24 and SP141.