Responses to crizotinib and chemotherapy in patients with lung adenocarcinoma harboring a concomitant EGFR mutation and ALK gene rearrangement: A case report and review of the literature.

Previous studies have indicated that, in lung cancers, the gene rearrangement of ALK is mutually exclusive with mutations in the epidermal growth factor receptor (EGFR) gene. However, the coexistence of EML4-ALK fusions and EGFR mutations (double positive) has been occasionally reported, with frequencies ranging from 0-8%. Currently, no consensus standard therapy exists for tumors with double positive mutations. In the present case report, the case is described of a 53-year-old woman with stage IV lung adenocarcinoma, harboring a concomitant EGFR mutation and ALK gene rearrangement, who was refractory to gefitinib administration but demonstrated a good response to crizotinib and pemetrexed chemotherapy. A review of the literature revealed a total of 65 cases, including our case, harboring double positive mutations, and of these cases, 39 (60.0%) patients had received an EGFR tyrosine kinase inhibitor (EHGR-TKI), and 15 (23%) patients had received crizotinib treatment, the majority of whom had crizotinib selected for them as a second-line or third-line therapy. The disease control rate (DCR) of EGFR-TKI was 72.2%, with the progression-free survival (PFS) being 11.9 months, whereas the DCR of crizotinib was 93.3%, with the PFS being 10 months.

Introduction

Previous studies have indicated that, in lung cancers, the gene rearrangement of ALK is mutually exclusive with mutations in the epidermal growth factor receptor (EGFR) gene (1). However, the coexistence of EML4-ALK fusions and EGFR mutations (double positive) has been occasionally reported in a small proportion of patients (2–27). Currently, there is no consensus opinion regarding the treatment of these patients with double positive molecular alterations. The effectiveness of precision therapy also remains unknown. The present study reports the case of a 53-year-old woman with stage IV lung adenocarcinoma, who was treated with first-line chemotherapy with a regime of cisplatin (75 mg/m2) and pemetrexed (PEM) (500 mg/m2) every three weeks up to four cycles, followed by PEM maintenance therapy. As the disease progressed, the patient underwent a repeat biopsy, which revealed mutation of the EGFR as well as an ALK gene rearrangement. Gefitinib administration proved to be ineffective, although crizotinib revealed a partial response (PR). In addition, all the cases reported in the English literature of concomitant EGFR mutations with ALK gene rearrangement were reviewed.

Case report

A 53-year-old female non-smoker was admitted to our hospital (The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China) for right chest discomfort in September 2013. A chest computed tomography (CT) scan revealed a 4.0×3.5 cm mass in the right upper lobe, with moderate pleural effusion (Fig. 1). The patient underwent thoracentesis. The pleural effusion specimen revealed the presence of malignant cells, which were positive for thyroid transcription factor-1 and negative for p63, consistent with metastatic lung adenocarcinoma (Fig. 2). EGFR mutational analysis was performed on the cell-block material using an amplification refractory mutation system (ARMS) technique (ADx-ARMS kit, Amoy Diagnostics, Xiamen, China). The experimental procedure followed, and data analysis performed, were precisely as described in the manufacturer's protocol. No EGFR mutations were identified in exons 18–21. On the basis of clinical assessment and further imaging studies, the patient was staged as stage IV lung cancer (cT2N0M1). The patient's performance status was 0 according to the Eastern Cooperative Oncology Group (ECOG) scale (28). The patient received a first-line chemotherapy with cisplatin (75 mg/m2) and PEM (500 mg/m2) every three weeks. Following four cycles of the treatment, a repeat CT scan revealed a PR (Fig. 3A and B). The patient was followed with maintenance PEM monotherapy (500 mg/m2) for 12 courses. While continuing to show stable disease (SD), the patient subsequently received radiotherapy for the right upper lobe lung mass, and she was kept on PEM monotherapy with SD, with the exception of small right pleural effusion (Fig. 3C and D).

Figure 1.

Chest CT images recorded prior to treatment. (A and B) In September 2013, prior to treatment, a chest CT scan revealed a right upper lobe mass and right pleural effusion. CT, computed tomography.

Figure 2.

Pathological evaluation of the pleural effusion specimen. The cell-block specimen of pleural effusion revealed adenocarcinoma. (A) Hematoxylin and eosin staining (magnification, ×400). (B) Immunoperoxidase staining (magnification, ×400), showed positive for thyroid transcription factor-1.

Figure 3.

A repeat CT scan recorded after four cycles of PEM combined with cisplatin chemotherapy. (A and B) In December 2013, following four cycles of PEM combined with cisplatin chemotherapy, the response was considered as a partial response. (C and D) In December 2014, following 15 cycles of PEM maintenance therapy and radiotherapy of the right upper lobe lesion, a chest CT revealed stable disease, with the exception of small right pleural effusion. CT, computed tomography; PEM, pemetrexed.

In March 2015, following 18 months of first-line treatment, the patient again complained of right chest pain and discomfort. A CT scan revealed the recurrence of pleural effusion (Fig. 4A and B), and the effusion specimen was re-evaluated for its pathological and molecular characteristics. In addition to malignant effusion, the cell-block material exhibited ALK gene rearrangement, which was confirmed by an automated immunohistochemistry (IHC) assay (Ventana pre-diluted ALK D5F3 antibody with the Optiview™ DAB IHC detection kit; Ventana Medical Systems, Inc., Tucson, AZ, USA) (Fig. 5A), and by reverse transcription-quantitative polymerase chain reaction (RT-PCR) assay (Fig. 5B). Notably, an EGFR mutation test performed on the current cell-block material revealed a deletion in exon 19 (delE746-A750; Fig. 5C). Overexpression of EGFR protein was also observed by the IHC assay, using an antibody raised against EGFR (rabbit anti-human EGFR monoclonal antibody; cat. no. RMA-0554, Fuzhou Maixin Biotechnology Development Co. Ltd., Fujian, China) (Fig. 5D).

Figure 4.

Chest CT images following 18 months of first-line treatment. (A and B) In March 2015, following 18 months of first-line treatment, a chest CT revealed right pleural effusion recurrence. CT, computed tomography.

Figure 5.

Re-evaluation of the effusion specimen for its pathological and molecular characteristics. (A) Positive ALK staining using a Ventana IHC assay (immunoperoxidase staining; magnification, ×400). (B) Positive ALK gene rearrangement using reverse transcription-polymerase chain reaction. (C) Presence of the EGFR mutation was revealed using the amplification refractory mutation system method. (D) Positive EGFR staining by IHC (immunoperoxidase staining, magnification ×400). IHC, immunohistochemistry; EGFR, epidermal growth factor receptor.

After the molecular test results has been revealed, the patient started to receive treatment with gefitinib (250 mg, once daily). However, no clinical response was achieved, and a new pleura-based mass (dimensions, 3.0×3.0 cm) was identified after two months of gefitinib therapy (Fig. 6A and B). A positron emission tomography (PET)-CT scan demonstrated multiple high metabolic lesions in the right upper lobe, the pleura, right ribs and in the liver under the capsule. In June 2015, the patient began to receive crizotinib (250 mg, twice per day), and she reported a rapid disappearance of discomfort and chest pain. After a further 6 months, the CT scan revealed a PR (Fig. 6C and D). The patient remained asymptomatic at the last follow-up, in April 2016, and at present, she continues to receive crizotinib with the same dose.

Figure 6.

Chest CT scans as the patient was administered treatments with gefitinib and crizotinib. (A and B) In May 2015, after 2 months' treatment with gefitinib, a new mass was observed close to the right pleura. (C and D) Following the crizotinib treatment, the pleural mass was reduced in size, and considered as a partial response.

This study was approved by the Ethics Committee of The First Affiliated Hospital of Wenzhou Medical University (Wenzhou, China). Written informed consent was obtained from the patient's next of kin.

Discussion

The prevalence of the coexistence of an ALK gene rearrangement and EGFR mutations may be variable, but it is generally low. Several studies have reported that the frequency ranges from 0–8% (24,29). Recently, Ulivi et al reported that double mutations were detected in 6 of the 380 (1.6%) patients with non-small cell lung cancer (NSCLC) (16). Different frequencies may be associated with ethnic differences of the patients and the assay detection sensitivity (13). The optimal treatment, however, has yet to be elucidated, since the responses to EGFR and/or ALK inhibitors have proven to be conflicting (3,4,9,17,19).

Based on a review of the English literature, a total of 65 cases were identified, including the present case, with concomitant EGFR mutations and ALK gene rearrangement. The cases with EGFR mutations detected by sensitive detection methods, such as RT-PCR, targeted next-generation sequencing (NGS), and mutant-enriched NGS, as well as repetitions of the identical cases reported in different journals, were excluded. The patients' clinicopathological characteristics and treatment outcomes are shown in Tables I and II. The patients included 32 women (49.2%) and 25 men (38.5%), with 9 (13.6%) patients of unknown sex. The mean age was 60 years old (ranging from 31–77 years). The patients of Asian ethnicity accounted for 56.9% (37 of 65) of the patients. The patients included 35 (56.9%) never smokers, 4 (6.2%) former smokers and 6 (9.2%) current smokers, with the smoking status unknown in 18 (27.7%) patients. The vast majority of patients (59 of 65 patients; 90.8%) were diagnosed with adenocarcinoma, with 35 cases (53.8%) being diagnosed at stages IIIb and IV. The EGFR mutations identified were exon 19 deletion in 34 (52.3%) and exon 21 (L858R) point mutation 19 (29.2%). ALK gene rearrangement was confirmed using fluorescence in situ hybridization (FISH) assay in 33 (50.8%) cases, by FISH and IHC in 9 (13.8%) cases, and by FISH and RT-PCR in 5 (7.76%) cases.

Table I.

Patients with concomitant EGFR mutations and ALK fusion.

Authors	Patient Age/sex	Ethnicity	Smoker	Histology	TNM stage	EGFR mutation	EGFR-TKI	Response	PFS (M)	ALK translocation	ALK-TKI	Response	PFS (M)	Chemotherapy	Response	(Refs.)
Miyanaga et al	55/F	A	No	AC	IV	Del exon 19	Gefitinib	SD	2	FISH, IHC, RT-PCR	Crizotinib	SD	4	Cis/Pem	SD	(2)
Chen et al	56/M	A	Current	AC	IV	Del exon 19	Erlotinib	SD	8	FISH, RT-PCR	Crizotinib	CR	22	Cis/Gem	NA (toxicity)	(3)
Chiari et al	67/F	C	Νο	AC	IV	L858R exon 21	Gefitinib	PR	27	FISH	Crizotinib	PR	25	Cis/Gem	SD	(4)
Baldi et al	68/M	C	Νο	AC	IV	L858R exon 21	Erlotinib	PR	37	FISH, IHC	Crizotinib	PR	10	Cis/Pem	SD	(5)
Zhao et al	48/F	A	Νο	AC	IV	L861Q exon 21	Erlotinib	SD	5.3	FISH	Crizotinib	SD	3.5	Ndp/Pem	PD	(6)
Zhou et al	47/F	A	Νο	AC	IV	Del exon 19	Gefitinib	PD	2	FISH, IHC	ND	NA	NA	Cis/Gem	PD	(7)
Tiseo et al	48/M	C	Νο	AdSq	IV	Del exon 19	Erlotinib	PD	NA	FISH	ND	NA	NA	Cis/Gem	PR	(8)
Popat et al	65/F	C	Νο	AC	IIIa	Del exon 19	Erlotinib	CR	25	FISH	ND	NA	NA	Carbo/Vin	PR	(9)
Tanaka et al	39/M	A	Current	AC	IV	L858R exon 21	Erlotinib	PD	1	RT-PCR, IHC	ND	NA	NA	Cis/Doc	SD	(10)
Jurgens et al	69/M	C	Current	AC	IV	L861Q exon 21	Gefitinib	PD	2	FISH	ND	NA	NA	Pem/Carbo/Beva	PR	(11)
Yang et al	65/F	A	Νο	AC	IIIa	Del exon 19	Erlotinib	PD	1.5	FISH, IHC	Crizotinib	PR	1.9	NA	NA	(12)
Yang et al	54/F	A	Νο	AC	IV	Del exon 19	Erlotinib	PR	12	FISH, IHC, RT-PCR	Crizotinib	SD	2.7	NA	NA	(12)
Yang et al	65/F	A	Νο	AC	IV	exon 20 insertion	Afatinib	PR	5	FISH, IHC	Crizotinib	PD	0.4	NA	NA	(12)
Yang et al	44/F	A	Νο	AC	IV	Del exon 19	Gefitinib	PR	9	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	40/M	A	Νο	AC	IV	Del exon 19	Erlotinib	PR	17.5	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	60/F	A	Νο	AC	IV	Del exon 19	Afatinib	SD	7	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	45/F	A	Νο	AC	IV	Del exon 19	ND	NA	NA	FISH, IHC, RT-PCR	Crizotinib	PR	15.1	NA	NA	(12)
Yang et al	56/F	A	Νο	AC	IV	L858R exon 21	Gefitinib	PR	11.2	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	66/F	A	Νο	AC	IV	L858R exon 21	Gefitinib	PR	24.5	FISH	NA	NA	NA	NA	NA	(12)
Yang et al	59/M	A	Νο	AC	IV	L858R exon 21	Erlotinib	PR	13	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	70/M	A	Νο	AC	IV	L858R exon 21	Erlotinib	PR	27.4	FISH, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	67/M	A	Νο	AC	IIIa	Del exon 19	ND	NA	NA	FISH, IHC, RT-PCR	NA	NA	NA	NA	NA	(12)
Yang et al	31/M	A	Current	AC	IV	K757R in exon 19	ND	NA	NA	FISH, RT-PCR	NA	NA	NA	NA	NA	(12)
Won et al	73/M	A	Former	AC	IV	Del exon 19	Gefitinib	PD	0.3	FISH, IHC	Crizotinib	PR	19	NA	NA	(13)
Won et al	62/M	A	Νο	AC	IV	L861Q exon 21	Gefitinib	SD	6	FISH	ND	NA	NA	NA	NA	(13)
Won et al	49/M	A	Νο	AC	Ia	L858R exon 21	ND	NA	NA	FISH	ND	NA	NA	NA	NA	(13)
Won et al	68/F	A	Νο	AC	IV	E868K exon 21	ND	NA	NA	FISH	ND	NA	NA	NA	NA	(13)
Kuo et al	72/F	A	Νο	AC	IV	Del exon 19	Gefitinib	PR	7	RT-PCR	ND	NA	NA	ND	NA	(14)
Xu et al	71/F	A	Νο	AC	IV	Del exon 19	Gefitinib	CR	8	FISH, RT-PCR	NA	NA	NA	NA	NA	(15)
Ulivi et al	72/F	C	Νο	AC	NA	Del exon 19	Gefitinib	CR	32	FISH	NA	NA	NA	NA	NA	(16)
Ulivi et al	52/F	C	Former	AC	NA	Del exon 19	Gefitinib	PR	10	FISH	NA	NA	NA	NA	NA	(16)
Ulivi et al	41/M	C	Νο	AC	NA	Del exon 19	Gefitinib	PD	2	FISH	NA	NA	NA	NA	NA	(16)
Ulivi et al	73/F	C	Former	AC	NA	Del exon 19	Erlotinib	PR	40	FISH	NA	NA	NA	NA	NA	(16)
Ulivi et al	54/F	C	Current	AC	NA	L858R exon 21	Gefitinib	PR	24	FISH	NA	NA	NA	NA	NA	(16)
Ulivi et al	68/F	C	Νο	AC	NA	E746-S752>S	Gefitinib	PD	2	FISH	NA	NA	NA	NA	NA	(16)
Lee et al[a]	NA/NA	A	NA	AC	IV	Del exon 19, A750P	Gefitinib	PD	0.3	FISH, IHC	Crizotinib	PR	9	NA	NA	(17)
Lee et al	NA/NA	A	NA	AC	IIB	E746-A750 deletion	NA	NA	NA	FISH, IHC	NA	NA	NA	NA	NA	(17)
Lee et al	NA/NA	A	NA	AC	IIIA	L718P	NA	NA	NA	FISH, IHC	NA	NA	NA	NA	NA	(17)
Lee et al	NA/NA	A	NA	AC	IA	L858R exon 21	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(17)
Sasaki et al	NA/NA	C	NA	NA	NA	Del exon 19	Erlotinib	PR	5	FISH	NA	NA	NA	NA	NA	(18)
Sasaki et al	NA/NA	C	NA	NA	NA	L858R exon 21	Erlotinib	PR	9	FISH	NA	NA	NA	NA	NA	(18)
Sasaki et al	NA/NA	C	NA	NA	NA	A767-V7-69dupASV	ND	NA	NA	FISH, IHC	NA	NA	NA	NA	NA	(18)
Sahnane et al	74/M	C	Νο	AC	IIIB- IV	G719A	Erlotinib	SD	8	FISH	Crizotinib	SD	NA	NA	NA	(19)
Sahnane et al	67/M	C	Νο	AC	IIIB- IV	Del exon 19	Erlotinib	PD	NA	FISH	Crizotinib	PR	NA	Carbo/Gem	NA	(19)
Sahnane et al	51/F	C	Unknown	AC	IIIB-IV	L858R exon 21	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(19)
Santelmo et al	52/F	C	Current	AC	IIIA	Del exon 19	Gefitinib	PR	NA	FISH	NA	NA	NA	NA	NA	(20)
Roossing et al[b]	61/M	C	Νο	AC	IV	L862R	NA	NA	NA	FISH, IHC	Crizotinib	PR	8	Carbo/Vin/Beva	PR	(21)
Cabillic et al	65/M	C	NA	AC	NA	L858R exon 21	Gefitinib	NA	NA	IHC	NA	NA	NA	NA	NA	(22)
Cabillic et al	62/M	C	NA	AC	NA	L858R exon 21	Gefitinib	NA	NA	FISH	NA	NA	NA	NA	NA	(22)
Cabillic et al	73/F	C	NA	NOS	NA	L858R exon 21	Gefitinib	NA	NA	FISH	NA	NA	NA	NA	NA	(22)
Cabillic et al	65/M	C	NA	AC	NA	L858R exon 21, T790M exon 20	NA	NA	NA	FISH	Crizotinib	PR	NA	NA	NA	(22)
Cabillic et al	77/F	C	NA	AC	IV	Del exon 19	NA	NA	NA	IHC	NA	NA	NA	NA	NA	(22)
Cabillic et al	52/M	C	NA	AC	NA	Del exon 19	NA	NA	NA	IHC	NA	NA	NA	NA	NA	(22)
Cabillic et al	65/F	C	NA	AC	NA	Del exon 19	NA	NA	NA	IHC	NA	NA	NA	NA	NA	(22)
Cabillic et al	68/M	C	NA	AC	NA	L858R exon 21	NA	NA	NA	IHC	NA	NA	NA	NA	NA	(22)
Zhu et al	54/F	A	Νο	AC	NA	Del exon 19	ND	NA	NA	FISH	NA	NA	NA	NA	NA	(23)
Zhu et al	61/F	A	Νο	AC	NA	Del exon 19	ND	NA	NA	FISH	NA	NA	NA	NA	NA	(23)
Zhang et al	NA/F	A	NA	AC	NA	Del exon 19	NA	NA	NA	RT-PCR	NA	NA	NA	NA	NA	(24)
Koivunen et al	NA/NA	NA	NA	AC	I–III	Del exon 19	NA	NA	NA	FISH, RT-PCR	NA	NA	NA	NA	NA	(25)
Kim et al	69/F	A	Νο	AC	IV	Del exon 19	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(26)
Kim et al	64/M	A	Former	AC	I	Del exon 19	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(26)
Kim et al	47/M	A	Νο	AC	IV	Del exon 19	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(26)
Kim et al	74/F	A	Νο	AdSq	IV	L858R exon 21	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(26)
Kim et al	59/M	A	Νο	AC	IV	L858R exon 21	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(26)
Wang et al	NA/NA	A	NA	AC	NA	L858R exon 21	NA	NA	NA	FISH	NA	NA	NA	NA	NA	(27)
Li et al	55/F	A	Νο	AC	IV	Del exon 19	Gefitinib	PD	2	IHC, RT-PCR	Crizotinib	PR	8	Cis/Pem	PR	The present study

The case has been described in Won et al (13), and was not calculated for the present study.

A case with EGFR, ALK and KRAS mutations in coexistence which were evaluated when the tumor relapsed. F, female; M, male; A, Asiatic; C, Caucasian; AC, adenocarcinoma; AdSq, adenosquamous; NOS, not otherwise specified; NSCLC, non-small cell lung cancer; CR, complete response; PR, partial response; SD, stable disease; PD, progression disease; FISH, fluorescence in situ hybridization; IHC, immunohistochemistry; RT-PCR, real time-polymerase chain reaction; Del, deletion; NA, not available; ND, not done; Cis, cisplatin; Carbo, carboplatin; Doc, docetaxel; Gem, gemcitabine; Ndp, nedaplatin; Pem, pemetrexed; Vin, vinorelbine; Beva, bevacizumab; NACT, neoadjuvant chemotherapy; EGFR, epidermal growth factor receptor; PFS, progression-free survival; TKI, tyrosine kinase inhibitor; TNM, tumor-lymph node-metastasis.

Table II.

Characteristics of patients with concomitant EGFR mutation and ALK fusion (n=65).

Characteristic	No. (%)
Age (median, range)	60 (31–77)
Sex
Male	25 (38.5)
Female	32 (49.2)
Unknown	8 (12.3)
Ethnicity
Asiatic	37 (56.9)
Caucasian	27 (41.5)
Unknown	1 (1.5)
Smoking status
Non-smokers	37 (56.9)
Former smokers	4 (6.2)
Current smokers	6 (9.2)
Unknown	18 (27.7)
Histology
Adenocarcinoma	59 (90.8)
Adenosquamous carcinoma	2 (3.1)
Not otherwise specified	1 (1.5)
Unknown	3 (4.6)
TNM stage
I–IIIa	10 (15.4)
IIIb-IV	35 (53.8)
Unknown	20 (30.8)
EGFR mutation
Del exon 19	34 (52.3)
L858R exon 21	19 (29.2)
L861Q exon 21	3 (4.6)
Others	9 (13.8)
ALK translocation
FISH	33 (50.8)
FISH + IHC	9 (13.8)
FISH + RT-PCR	5 (7.7)
FISH + IHC+RT-PCR	9 (13.8)
IHC	5 (7.7)
RT-PCR	2 (3.1)
IHC + RT-PCR	2 (3.1)
EGFR-TKI (n=39)
Gefitinib	21 (53.8)
Erlotinib	16(41.6)
Afatinib	2 (5.1)
Response to EGFR-TKI (n=36)
CR/PR/SD	26 (72.2)
PD	10 (27.8)
PFS of EGFR-TKI, months (median, range) (n=33)	11.9 (0.3–40)
Response to ALK-TKI (crizotinib; n=15)
CR/PR/SD	14 (93.3)
PD	1 (6.7)
PFS of ALK-TKI, months (median, range) (n=12)	10 (0.4–25)
Response to chemotherapy (n=12)
CR/PR/SD	9 (75.0)
PD	3 (25.0)

Del, deletion; EGFR, epidermal growth factor receptor; FISH, fluorescent in situ hybridization; IHC, immunohistochemistry; RT-PCR, real time-polymerase chain reaction; CR, complete response; PR, partial response; SD, stable disease; PD, progression disease; PFS, progression-free survival; TNM, tumor-lymph node-metastasis.

The efficacy of EGFR-TKI treatments for tumors that were double positive remains inconclusive. From the data presented in Tables I and II, it was noted that 39 (60.0%) patients had received an EGFR-TKI, 21 (53.8%) with gefitinib, 16 (41.6%) with erlotinib, and 2 (5.1%) with afatinib. Detailed information about the response to TKIs was provided for 36 patients. Among them, 26 (72.2%) patients showed a complete response (CR), PR, or SD (disease control rate, DCR), whereas a further 10 (27.8%) patients experienced progression of disease (PD). The median PFS of EGFR-TKIs was 11.9 months (ranging from 0.3–40 months) in 33 patients, which was similar to the PFS of EGFR-TKI treatment in patients who had the EGFR mutation alone. Zhao et al (6) reported a case of double positive mutations that benefited from a short period treatment of three TKIs. Baldi et al (5) described a case of a double positive NSCLC, in which a good clinical response was observed not only with erlotinib, but also with the ALK inhibitor, crizotinib. However, there are other studies that included double positive patients who did not respond to EGFR-TKIs, but achieved a good response to ALK inhibitors (12,13,17). As illustrated in our case, the patients received EGFR-TKI as a second-line therapy, but exhibited PD, including the occurrence of a new pleura-based mass. Subsequently, crizotinib was administered as a third-line treatment, which revealed a dramatic response. Similar results were reported by Lee et al (17). These authors reported a case of ALK-positive and EGFR-mutant NSCLC patient who did not respond to EGFR-TKI, but achieved a partial response to ALK inhibitors. From the literature review, only 15 (23%) patients received crizotinib treatment, the majority of whom had crizotinib selected for them as a second-line or third-line therapy. In 12 patients, the DCR was 93.3% and the median PFS was 10 months (0.4–25 months). Recently, Won et al (13) reported that EGFR-TKIs were not effective in double positive patients, whereas ALK inhibitors were efficient (13). In their study, the majority (7 of 8) patients treated with ALK inhibitors exhibited EGFR mutations by peptide nucleic acid-clamping RT-PCR and/or NGS, but not by Sanger sequencing, which may suggest the possibility of a low burden of EGFR mutants in these patients, although a complete explanation underpinning the lack of response to gefitinib remains unknown. Similarly, Sahnane et al (19) showed that patients with ALK/EGFR mutations might benefit from crizotinib, rather than erlotinib administration. In double positive patients, whichever target drug is more effective may depend on the levels of the two driver gene molecular alterations. From Table II, it was also noted that 12 patients had received chemotherapy, with the DCR being 75%. In the present case study, PEM therapy and crizotinib revealed a good response, and ALK gene rearrangement may have been the primary driven gene mutation. Park et al (30) demonstrated that ALK-positive patients had a greater response rate (RR) and longer PFS with PEM-based chemotherapy compared with the patients with EGFR mutations or without an ALK gene rearrangement. The RRs were 26.9, 12.8 and 18.5%, respectively; the PFSs were 7.8, 2.5 and 2.9 months, respectively.

The phenomenon of double positive mutations in NSCLCs may be explained by the heterogeneity of tumor cells: Different genetic alterations may occur in different tumor cells, or multiple oncogenic pathways may be altered in a single clone of tumor cells. Recently, Sahnane et al (19) reported the frequencies of mutant alleles and their gene dosage in double positive patients, suggesting that the EGFR mutation occurs as the first event, and ALK alterations, primarily identified in advanced lung adenocarcinomas, occur late during tumor progression.

With the introduction of precision-targeted therapy in NSCLC and the application of advanced molecular/genetic techniques, more double positive NSCLC patients would be identified. Won et al (13) detected four double positive cases in 1,458 cases of lung cancers for EGFR and ALK alterations by Sanger sequencing and the FISH technique, respectively. However, they identified additional 10 dual positive cases when more sensitive assays were used.

Repeat biopsies are crucial in managing patients with tumor recurrences. As in the present case study, the biopsies offered the opportunity to reassess the mutation profile, which is invaluable for choosing appropriate treatment options. Since the majority of patients with NSCLC are diagnosed through small samples, the tumor heterogeneity or relatively low number of tumor cells may lead to false negative results of EGFR mutations and ALK gene rearrangement. Hence, when obtaining small samples, it is crucial to maximize the number of samples available for molecular studies. Furthermore, in cases that tested positive for EGFR mutations, particularly when the tumors failed to respond to EGFR-TKI treatment, it is important to consider the possibility of double positive mutations, since EGFR mutations and ALK gene rearrangement do coexist in certain tumors.

In conclusion, in the present study, a case of lung adenocarcinoma with concomitant EGFR mutation and ALK gene rearrangement has been reported, which was refractory to gefitinib administration, but exhibited a good response to crizotinib and PEM chemotherapy. A review of the literature demonstrated that the frequencies of coexistence of ALK gene rearrangement and EGFR mutations ranged from 0–8%. Currently, there is no consensus standard therapy for tumors with double positive mutations. In cases with double positive mutations, the DCR of EGFR-TKI was reported to be 72.2%, with the PFS being 11.9 months, whereas the DCR of crizotinib was 93.3%, with the PFS being 10 months.