In this report, we described the first case of squamous cell carcinoma (SCC) transformation from adenocarcinoma (ADC) in NSCLC with ALK rearrangement after treatment with ALK TKI.
There were two cases in which recurrence developed over 15 years after the resection; both cases were of adenocarcinoma with anaplastic lymphoma kinase (ALK) rearrangement.
Positive ALK test results were more common in patients with invasive mucinous adenocarcinoma and solid-predominant invasive adenocarcinoma than in patients with other histotypes.
After biopsy, the abdominal lymph nodes were identified as adenocarcinoma originating from the lung following computed tomography (CT) scan, and ALK rearrangement was confirmed.
The results highlight the importance of distinguishing synchronous primary tumors from intrapulmonary metastases, and of assessing the relative abundance of EGFR mutation and ALK rearrangement in patients with multifocal adenocarcinomas with EGFR/ALK co-alterations.
<i>ALK</i> positivity was significantly associated with younger age (P<0.001), solid predominant adenocarcinoma (P<0.001), variants of invasive adenocarcinoma (P<0.001), higher frequency of pleura invasion (P=0.040), smaller tumor size (P=0.014), mediastinal lymph node involvement (N2; P<0.001) and later pathologic stage (IIIA; P=0.001).
The favor ADC group tended to have a higher percentage of EGFR positivity and ALK positivity than the favor SQC group (25% vs. 11% and 7% vs. 0%, respectively).
Histologic transformation from adenocarcinoma to squamous cell carcinoma in lung cancer has not been reported as a mechanism of resistance to ALK inhibition.
Anaplastic lymphoma kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations.
This study was aimed at investigating the prognostic significance of Baculoviral IAP repeat containing 5 (BIRC5) in lung adenocarcinoma (LAD) lacking EGFR, KRAS, and ALK mutations (triple-negative (TN) adenocarcinomas).
Medical management did not improve outcomes, except for two ALK receptor tyrosine kinase (ALK)-rearranged adenocarcinomas that responded to ALK inhibitor therapy alone.
This review summarizes the hot topics of immunohistochemistry in lung cancer, including (i) adenocarcinoma vs squamous cell carcinoma; (ii) neuroendocrine markers; (iii) ALK, ROS1, and EGFR; (iv) PD-L1 (CD274); (v) lung carcinoma vs malignant mesothelioma; and (vi) NUT carcinoma.
Herein, we report the case of a 42-year-old male patient diagnosed with adenocarcinoma with different histomorphologies in the primary lung site (mucinous type) and lymph node metastasis (solid type), of the same genotype, both presenting with ALK rearrangement but negative for EGFR mutation.
On FISH and IHC using cell block material, ALK rearrangement and ALK protein expression were identified again, along with recurrent ALKadenocarcinoma cells, which were observed to have an increased ALK copy number compared with the primary ALKadenocarcinoma cells.