Detecting EGFR alterations in clinical specimens—pitfalls and necessities

First-line programmed death receptor-1 (PD-1) inhibitor and epidermal growth factor receptor (EGFR) blockade, combined with platinum-based chemotherapy, for stage IV penile cancer

OBJECTIVES

To evaluate the anti-tumour activity and safety of anti-programmed death receptor-1 (PD-1) antibody plus epidermal growth factor receptor blockade combined with platinum-based chemotherapy (PEP) as first-line therapy for stage IV penile squamous cell carcinoma (PSCC).

PATIENTS AND METHODS

We conducted a retrospective review of 17 patients with stage IV PSCC undergoing first-line PEP at Sun Yat-sen University Cancer Center between January 2018 and September 2021. Clinical responses were assessed using the Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Adverse events (AEs) were graded according to Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

Of 17 patients who received first-line PEP, 13 were observed to have partial responses. Twelve patients subsequently received consolidated surgery. Nine of these achieved pN0 status, of whom six with locally advanced PSCC achieved pathological complete response. The median (range) follow-up time was 24.87 (3.63-29.40) months. Median PFS and median OS were not reached, with 2-year PFS and OS rates being 68.4% (95% confidence interval [CI] 48.7-96.1) and 62.9% (95% CI 41.6-95), respectively. Eight patients experienced Grade 3 or 4 treatment-related AEs. No Grade 5 AEs or death associated with treatment was observed.

CONCLUSIONS

Anti-PD-1 antibody plus epidermal growth factor receptor blockade and platinum-based chemotherapy showed promising anti-tumour activity, acceptable toxicity, and satisfying long-term survival for stage IV PSCC. Larger clinical trials are needed to validate our findings.

Epidermal Growth Factor Receptor Mutation Frequency in Squamous Cell Carcinoma and Its Diagnostic Performance in Cytological Samples: A Molecular and Immunohistochemical Study

Background

Epidermal growth factor receptor (EGFR) mutation is the most frequent mutation tested in lung cancer for targeted therapy in the era of personalized medicine. Knowledge about EGFR mutation is constantly expanding regarding its frequency, clinicopathological association, advancements in testing methodology and sample requirement. We investigated EGFR mutation frequency in non-small cell lung cancer (NSCLC) in North Indian patients and evaluated its diagnostic performance in cytological samples.

Methods

Molecular EGFR testing was done in 250 cases of NSCLC by both real-time polymerase chain reaction (PCR) (Therascreen) and mutation-specific EGFR immunohistochemistry (IHC). Thirty cases had both cytology samples and biopsy including 20 pleural effusions and 10 fine-needle aspirates. EGFR mutation concordance between pleural effusion and biopsy was studied.

Results

EGFR mutation was overall 31.6% in NSCLC with 36.5% in adenocarcinoma and 15% in squamous cell carcinoma. L858R mutation accounted for 50.7% and DEL19 for 39.3% of total EGFR mutations. Complex mutations were seen in 2% of cases. Sensitivity of mutation-specific EGFR IHC was 48.3% and specificity was 92.3%. L858R showed higher sensitivity (55% vs. 33.3%) but similar specificity (93.2% vs. 91.3%) compared to DEL19. EGFR mutation was successful in 95% of pleural effusion and showed 83.3% concordance with tissue biopsy.

Conclusions

EGFR mutation frequency in North Indian patients was comparable to that of Asia-Pacific region and showed a similar pattern of histological distribution. EGFR mutation in squamous cell carcinomas is increasingly recognized which was 15% in our study. Mutation-specific EGFR IHC shows variable but generally low sensitivity and considering its significant pre- and post-analytical variables, it should be highly discouraged in patient management. Cytological samples may not only serve as suitable alternative but may be complementary to tissue biopsies.

Epidermal growth factor receptor as an adverse survival predictor in squamous cell carcinoma of the penis

Penile carcinoma (PC) is more frequent in underdeveloped countries, generally is diagnosed at an advanced stage when therapeutic options are restricted, and thus is associated with high morbidity/mortality rates. Recent studies have demonstrated clinical benefits with epidermal growth factor receptor (EGFR)-targeted therapy in patients with PC, although there is no test that provides accurate patient selection. The aim of the present study was to evaluate the prognostic value of EGFR gene and protein status in tumor samples from patients with primary penile squamous cell carcinoma. We assessed the expression of wild-type and 2 mutant EGFR isoforms (delA746-E750 and mL858R) by immunohistochemistry in 139 samples, of which 49 were also evaluated for EGFR copy number by fluorescence in situ hybridization (FISH). Positive immunohistochemical staining of wild-type and mutant EGFR was evidenced by complete and strong membranous staining. For FISH analysis, cases were considered unaltered, polysomic, or amplified, as determined by signals of the EGFR gene and chromosome 7. An independent cohort of 107 PC samples was evaluated for mutations in EGFR, KRAS, and BRAF. Protein overexpression was noted in nearly half of the cases and was associated with cancer recurrence (P=.004) and perineural invasion (P=.005). Expression of the 2 mutated EGFR isoforms was not observed. The FISH status was not associated with protein expression. Altered FISH (polysomy and gene amplification) was an independent risk factor for dying of cancer. Only 1 patient of 107 presented KRAS mutations, and no mutations of EGFR or BRAF were observed.