Dual surrogate markers for rapid prediction of epidermal growth factor receptor mutation status in advanced adenocarcinoma of the lung: A novel approach in resource-limited setting

Relationship Between TTF-1 Expression and PFS of Pemetrexed-containing Chemotherapy in Non-squamous-NSCLC Patients With and Without Driver Genes

BACKGROUND/AIM

We performed a retrospective study too clarify whether the presence or absence of driver genes affects the relationship between thyroid transcription factor-1 (TTF-1) expression and response to pemetrexed (PEM) in non-squamous non-small cell lung cancer (non-sq-NSCLC) patients.

PATIENTS AND METHODS

We reviewed the medical charts of patients treated with PEM-containing chemotherapy during the period from February 2016 to February 2022 at Mito Medical Center-University of Tsukuba, Ryugasaki Saiseikai General Hospital, and University of Tsukuba Hospital.

RESULTS

During the period of the study, 185 driver gene-negative patients negative, and 65 driver gene-positive patients were evaluated. Among the 165 driver gene-negative patients, progression free survival (PFS) of TTF-1-expressing patients treated with PEM-containing chemotherapy was significantly longer compared to that of TTF-1-negative patients. In the analysis of 65 driver gene-positive patients, the PFS of TTF-1-positive patients treated with PEM-containing chemotherapy did not differ significantly from that of TTF-1-negative patients. There was no significant difference in PFS between driver gene-negative and driver gene-positive patients treated with PEM-containing chemotherapy. Comparison between four groups defined according to the presence of driver gene and TTF-1 expression indicated shorter PFS only in 'driver gene-negative and TTF-1-negative' patients.

CONCLUSION

In driver gene-positive non-sq NSCLC patients, expression of TTF does not affect the survival outcome of PEM-containing-chemotherapy. In other words, in these patients, second-line or later-line PEM-containing chemotherapy after development of resistance for specific-tyrosine kinase inhibitor could be expected to have the same level of efficacy as first-line PEM containing chemotherapy in driver gene-negative, TTF-1-positive non-sq NSCLC patients.

Correlation of TTF-1 immunoexpression and EGFR mutation spectrum in non-small cell lung carcinoma

Background

Thyroid transcription factor (TTF-1) is a diagnostic marker expressed in 75%–85% of primary lung adenocarcinomas (ACs). Activating mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene is the most common targetable driver alteration in lung AC. Previous studies have shown a positive correlation between TTF-1 and EGFR mutation status. We aimed to determine the predictive value of TTF-1 immunoexpression for underlying EGFR mutation status in a large Indian cohort.

Methods

This retrospective designed study was conducted with medical record data from 2011 to 2020. All cases of primary lung AC and non–small cell lung carcinoma not otherwise specified (NSCLC, NOS) with known TTF-1 expression diagnosed by immunohistochemistry using 8G7G3/1 antibodies and EGFR mutation status diagnosed by quantitative polymerase chain reaction were retrieved, reviewed, and theresults were analyzed.

Results

Among 909 patient samples diagnosed as lung AC and NSCLC, NOS, TTF-1 was positive in 76.8% cases (698/909) and EGFR mutations were detected in 29.6% (269/909). A strong positive correlation was present between TTF-1 positivity and EGFR mutation status (odds ratio, 3.61; p < .001), with TTF-1 positivity showing high sensitivity (90%) and negative predictive value (87%) for EGFR mutation. TTF-1 immunoexpression did not show significant correlation with uncommon/dual EGFR mutations (odds ratio, 1.69; p = .098). EGFR–tyrosine kinase inhibitor therapy was significantly superior to chemotherapy among EGFR mutant cases irrespective of TTF-1 status; however, no significant differences among survival outcomes were observed.

Conclusions

Our study confirms a strong positive correlation between TTF-1 expression and common EGFR mutations (exon 19 deletion and exon 21 L858R) in advanced lung AC with significantly high negative predictive value of TTF-1 for EGFR mutations.

Correlation of Thyroid Transcription Factor-1 Expression with EGFR Mutations in Non-Small-Cell Lung Cancer: A Meta-Analysis

OBJECTIVES

This meta-analysis investigated the relationship between thyroid transcription factor-1 (TTF-1) expression and epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer (NSCLC) to clarify whether TTF-1 can be a potential surrogate marker for EGFR mutation status in advanced NSLCL.

METHODS

A systematic searching of databases, including PubMed, EMBASE, Cochrane Library, and Google Scholar, was performed to identify studies assessing the correlation of TTF-1 expression with EGFR mutations. From 17 studies, 9764 patients were included in the combined analysis of odds ratio (OR) for the correlation between TTF-1 expression and EGFR mutations.

RESULTS

Compared with NSCLCs showing negative TTF-1 expression, tumors harboring TTF-1 overexpression showed a significantly higher rate of EGFR mutations (OR = 5.19, 95% confidence interval: 3.60⁻7.47, p < 0.00001). This correlation was observed in both subgroups of East Asian (OR = 4.33, 95% CI: 3.46⁻5.41, p < 0.00001) and European patients (OR = 4.64, 95% CI: 1.41⁻15.28, p < 0.01). In addition, TTF-1 expression was significantly associated with EGFR mutations in exon 19 (OR = 4.63, 95% CI: 2.89⁻7.41, p < 0.00001) as well as exon 21 (OR = 3.16, 95% CI: 1.04⁻9.60, p = 0.04).

CONCLUSIONS

This meta-analysis demonstrates a significant correlation between TTF-1 expression and EGFR mutations in patients with NSCLC. The status of TTF-1 expression may be a biomarker to guide anticancer treatment in patients with NSCLC and unknown EGFR mutation status.

Surfactant Protein A and Napsin A in the Immunohistochemical Characterization of Canine Pulmonary Carcinomas: Comparison With Thyroid Transcription Factor-1

Thyroid transcription factor-1 (TTF-1) is a specific and sensitive marker for canine pulmonary tumors but is also expressed in thyroid carcinomas, which commonly metastasize to lung. Napsin A and surfactant protein A (SP-A) are used in the histologic diagnosis of non-small-cell lung cancer in humans but have not been thoroughly evaluated in neoplasms of dogs. The objective of this study was to compare the efficacy of immunohistochemistry for SP-A, napsin A, and TTF-1 in the diagnosis of canine pulmonary carcinomas. TTF-1, napsin A, and SP-A antibodies were applied to 67 formalin-fixed, paraffin-embedded canine pulmonary tumors. Although each marker had good sensitivity, only 3% (2/67) of lung tumors were negative for SP-A compared with 7% (5/67) and 9% (6/67) for napsin A and TTF-1, respectively. Each antigen was detected in a greater percentage of cells of tumors with acinar or papillary patterns compared with those with squamous differentiation. SP-A immunoreactivity was absent in all 113 nonpulmonary tumors tested. Of 108 normal tissues, SP-A was detected only in lung and in 1 of 6 adrenal, 1 of 3 endometrial, and 1 of 4 hepatic sections. Based on these findings, SP-A and napsin A are useful markers of canine lung epithelial neoplasia. Of these, SP-A is the most sensitive and specific (a possible pitfall is the need to distinguish entrapped normal pulmonary epithelial cells or alveolar macrophages from neoplastic cells) and can be used in combination with TTF-1 or napsin A to improve detection and differentiation of pulmonary carcinomas from metastatic tumors in the canine lung.