Evaluation of immunohistochemistry using two different antibodies and procedures for primary lung adenocarcinoma harboring anaplastic lymphoma kinase rearrangement

ALK protein expression in pulmonary adenocarcinoma of Tunisian patients

BACKGROUND

It is now necessary to determine ALK status in order to use targeted therapy.

AIM

herein, we assess immunohistochemical profile of ALK protein in a series of Tunisian patients with pulmonary adenocarcinoma.

MATERIALS AND METHODS

ALK protein expression was studied applying the D5F3 antibody with a fully automated Ventana CDx technique on a series of 19 patients.

RESULTS

Positive ALK expression was found in one case (5.2%) corresponding to a papillary adenocarcinoma which showed a strong granular and homogenous cytoplasmic staining. The patient was a 30-years-old woman.

CONCLUSION

The frequency of positive ALK expression based on immunohistochemistry in our series was similar to that reported in the world literature.

Heterogeneity of anaplastic lymphoma kinase gene rearrangement in non-small-cell lung carcinomas: a comparative study between small biopsy and excision samples

INTRODUCTION

The standard diagnostic method for echinoderm microtubule-associated protein-like 4-anaplastic lymphoma receptor tyrosine kinase translocation is fluorescence in situ hybridization (FISH). Recently, immunohistochemistry (IHC) has been reported as a potential method in screening for anaplastic lymphoma kinase (ALK)-positive non-small-cell lung carcinomas (NSCLC), whereas several authors have reported a discordance between FISH and IHC results. We investigated the heterogeneity of ALK gene rearrangement in excision specimens by FISH and also examined whether the FISH score of ALK gene rearrangement corresponded in excision and biopsy samples from the same patient.

METHODS

Twenty ALK IHC-positive patients including six patients treated with crizotinib therapy were evaluated for the presence of ALK FISH. For evaluation of heterogeneity of ALK gene rearrangement in excision specimens, we defined six to 10 observation areas in each case, and the number of ALK FISH positive observation areas (≥15% rearrangement detected) was investigated. ALK FISH score in small biopsy samples was classified as positive (≥15% rearrangement detected), equivocal (5-14% rearrangement detected), or negative (<4% rearrangement detected).

RESULTS

Of a total of 64 tumor observation areas from nine excision specimens, 50 areas were positive for ALK gene rearrangement (81.8%). In the comparison of excision and small biopsy samples, all excision specimens were ALK FISH-positive (100%; 6 of 6), whereas only three of the small biopsy samples in these patients were positive (50%; 3 of 6), two were equivocal (33%; 2 of 6), and one was negative (17%; 1 of 6). The two equivocal patients received crizotinib and showed a response.

CONCLUSION

ALK gene rearrangement heterogeneity was observed in NSCLC specimens by FISH. Our findings suggested that IHC-positive/FISH-equivocal cases should not be considered true "false-negatives" when a small biopsy sample was used for ALK analysis.

Efficacy and tolerability of crizotinib in the treatment of ALK-positive, advanced non-small cell lung cancer in Chinese patients

Crizotinib has been reported to be particularly effective and to have acceptable toxicity in advanced anaplastic lymphoma kinase (ALK)-positive, non-small cell lung cancer (NSCLC). In this study, we analyzed the efficacy and tolerability of crizotinib in the treatment of 72 Chinese patients with ALK-positive, advanced NSCLC. All patients received oral crizotinib 250 mg twice daily in 28-day cycles during the period June 1, 2013, to October 15, 2014. The tumor response was assessed after the first cycle of crizotinib and then after every two cycles using the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.0. Tolerability was assessed at least twice per cycle until crizotinib was discontinued. The patients tended to be young (mean age 55 years, range 31-83 years), never or light smokers (smoking index <400), and to have an adenocarcinoma histology. Most (49/72; 68.1 %) had received previous anticancer treatment before crizotinib therapy. Sixty-seven patients (93 %) were able to be assessed for efficacy. The objective response rate and disease control rate were 52.2 % (95 % CI 40.5-63.9 %) and 64.2 % (95 % CI 52.75-75.7 %), respectively. The estimated median progression-free survival for all 67 patients was 10.3 months (95 % CI 8.6-12.0 months). Mild visual disturbances, nausea, vomiting, diarrhea and constipation were the most commonly reported adverse effects. Thus, crizotinib was well tolerated and showed promising efficacy in Chinese patients with ALK-positive, advanced NSCLC. Further prospective, multicenter studies with a larger sample size are needed to confirm these findings.