In previous years, three‑dimensional (3D) cell culture technology has become a focus of research in tumor cell biology, using a variety of methods and materials to mimic the in vivo microenvironment of cultured tumor cells ex vivo. These 3D tumor cells have demonstrated numerous different characteristics compared with traditional two‑dimensional (2D) culture. 3D cell culture provides a useful platform for further identifying the biological characteristics of tumor cells, particularly in the drug sensitivity area of the key points of translational medicine. It promises to be a bridge between traditional 2D culture and animal experiments, and is of great importance for further research in the field of tumor biology. In the present review, previous 3D cell culture applications, focusing on anti‑tumor drug susceptibility testing, are summarized.

Aldehyde dehydrogenase 1 family member A1 (ALDH1A1) has been identified as a putative cancer stem cell (CSC) marker in breast cancer. However, the clinicopathological and prognostic significance of this protein in breast cancer patients remains controversial. This meta-analysis was conducted to address the above issues using 15 publications covering 921 ALDH1A1⁺ cases and 2353 controls. The overall and subcategory analyses were performed to detect the association between ALDH1A1 expression and clinicopathological/prognostic parameters in breast cancer patients. The overall analysis showed that higher expression of ALDH1A1 is associated with larger tumor size, higher histological grade, greater possibility of lymph node metastasis (LNM), higher level expression of epidermal growth factor receptor 2 (HER2), and lower level expression of estrogen receptor (ER)/progesterone receptor (PR). The prognosis of breast cancer patients with ALDH1A1⁺ tumors was poorer than that of the ALDH1A1^- patients. Although the relationships between ALDH1A1 expression and some clinicopathological parameters (tumor size, LNM, and the expression of HER2) was not definitive to some degree when we performed a subcategory analysis, the predictive values of ALDH1A1 expression for histological grade and survival of breast cancer patients were significant regardless of the different cutoff values of ALDH1A1 expression, the different districts where the patients were located, the different clinical stages of the patients, the difference in antibodies used in the studies, and the surgery status. Our results indicate that ALDH1A1 is a biomarker to predict tumor progression and poor survival of breast cancer patients. This marker should be taken into consideration in the development of new diagnostic and therapeutic program for breast cancer.

Rationale: Mutation p.A289V involving extracellular region of epidermal growth factor receptor (EGFR) exon 7 has not yet been reported in nonsmall cell lung cancer (NSCLC). Studies have shown p.A289V mutation responding to tyrosine kinase inhibitors (TKIs) in glioblastoma cell lines suggesting the point mutation as a potential therapeutic target. However, sufficient evidence of the effect of TKI treatment on the p.A289V mutation involved in NSCLC is not available. Patient concerns: An 80-year-old nonsmoker male with lung mass was suffering from severe bone pain. Diagnosis: Needle biopsy and positron emitted tomography/computed tomography were performed. The patient was diagnosed with advanced NSCLC adenocarcinoma with bone and lymphatic metastasis. Next-generation sequencing of circulating tumor DNA was performed, which identified a p.A289V mutation in the EGFR gene of the patient. Interventions: Our patient refused to receive chemotherapy and tried Icotinib treatment. Outcomes: Our patient had a partial response to Icotinib after treatment for 5 months during the therapeutic trial by TKIs. The patient showed adverse symptoms of mild diarrhea and rash (Common Terminology Criteria for Adverse Events grade 1) during the treatment. Lessons: In this case, Icotinib prevented completion of the signal transduction cascade of p.A289V mutant in NSCLC. Our finding may expand the EGFR mutation spectrum for TKI treatment in NSCLC. However, the finding needs to be confirmed at a larger scale with NSCLC in Chinese and other populations.

Carcinoma metastatic to the eye is a rare condition, typically associated with a poor prognosis. Breast and lung cancers are the most common sources of intraocular metastases, and the majority of metastatic lesions involve the posterior uvea, with <8% of reported cases arising in the iris. Intraocular metastasis as the presenting form of esophageal carcinoma is highly uncommon. In the present report, a rare case of metastatic iris tumor resulting from esophageal squamous cell carcinoma is discussed. A 64-year-old patient presented with a progressively distending pain in the right eye, with associated blurred vision. Local and systemic evaluation was performed, followed by treatment. Multiple examinations identified a neoplasm in the right iris and postoperative pathology revealed that the iris lesion was a metastasis of esophageal squamous cell cancer origin. The patient was treated with adjuvant radiation. To the best of our knowledge, this was only the second reported case of esophageal squamous cell carcinoma metastasizing to the iris.

Gastric cancer rarely metastasizes to the oral cavity, especially to gingiva. Only 18 cases have been reported worldwide to date. This paper herein presents the nineteenth case of gingival metastasis from gastric cancer. A 75-year-old man who underwent a radical gastrectomy for gastric adenocarcinoma was admitted to clinical oncology center for gingival mass which was originally diagnosed as epulis. The subsequent positron emission tomography-computed tomography (PET-CT) and histopathological examination revealed a gingival metastatic adenocarcinoma originated from gastric carcinoma. Then three-dimensional conformal radiotherapy (3D–CRT) with synchronization and sequential chemotherapy demonstrated clinical benefit in this patient. Furthermore, this research reviewed the records of 18 cases of gingival metastasis from gastric carcinoma in English, Japanese, and Chinese literature, and summarized the clinicopathologic features of the disease based on previously published papers. This case suggests that gingival metastasis from gastric cancer is worthy of vigilance. Biopsy and immunohistochemical (IHC) staining should be used for the final diagnosis. Moreover, the patient with uncommon gingival metastatic lesion can be successfully treated by radiotherapy with adjuvant chemotherapy.