Incidence, clinicopathological features, and clinical outcomes of low HER2 expressed, inoperable, advanced, or recurrent gastric/gastroesophageal junction adenocarcinoma

BACKGROUND

According to the DESTINY-Breast04 trial, treating patients with breast cancer and low human epidermal growth factor receptor 2 expressions (HER2-low) varies from that of those with no HER2 expression. However, it is interesting to know if HER2-low indicates for anti-HER2 therapy in the gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Hence we conducted this study to assess the incidence, clinicopathological features, and treatment outcomes of patients with HER2-low G/GEJ adenocarcinoma.

PATIENTS AND METHODS

This was a single-center, retrospective observational study. Patients with previously untreated G/GEJ adenocarcinoma were classified based on their HER2 status using immunohistochemistry (IHC) with or without in situ hybridization (ISH) as follows: HER2 negative (IHC 0), HER2-low (IHC 1+ or 2+/ISH-), and HER2-positive (IHC2+/ISH+ or 3+).

RESULTS

In total, 734 patients with G/GEJ adenocarcinoma were divided into three groups (HER2-negative, n = 410; HER2-low, n = 154, and HER2-positive, n = 170). The intestinal-type histology, peritoneal metastasis, and higher serum carcinoembryonic antigen (CEA) levels differed significantly among patients with negative, low, and positive HER2 statuses: intestinal-type histology (21.0%, 44.2%, and 59.8%, respectively), peritoneal metastasis (56.3%, 44.8%, and 21.8%, respectively), and higher serum CEA level (32.2%, 41.6%, and 56.5%, respectively). Improved survival was observed in the HER2-positive group than in the HER2-negative G/GEJ adenocarcinoma group [hazard ratio (HR) = 0.73, 95% confidence interval (CI) 0.59-0.89; P = 0.002]. However, the prognoses of the HER2-low and HER2-negative groups were similar (HR = 1.01, 95% CI 0.82-1.23; P = 0.843).

CONCLUSIONS

Patients with HER2-low G/GEJ adenocarcinoma exhibited intermediate and distinct characteristics than those in the HER2-negative group. Similarly, the HER2-low group's prognosis was worse than that of the HER2-positive group. Therefore developing novel therapeutic strategies targeting HER2-low G/GEJ adenocarcinoma is required.

Genomic gain of the PRL-3 gene may represent poor prognosis of primary colorectal cancer, and associate with liver metastasis

PRL-3 genomic copy number is increased in colorectal cancer (CRC), and PRL-3 expression is closely associated with lymph node and liver metastasis of CRC. However, the clinical significance of PRL-3 genomic gain for CRC remains obscure. Here, PRL-3 genomic status in 109 primary CRC tumors and in 44 CRC tumors that had metastasized to the liver, was quantified using real time PCR. Association of PRL-3 genomic status with clinicopathological factors and prognosis was assessed in detail. PRL-3 genomic gain was identified in 31 primary CRC (27.4 %) and was more frequently seen in stage III than in stage II (p = 0.025). Among the clinicopathological factors assessed, PRL-3 genomic gain was significantly associated with poorly differentiated histology (p = 0.0039). Moreover, CRC patients with PRL-3 genomic gain exhibited poorer prognosis than those with no gain in stage II-IV CRC (p = 0.017). PRL-3 genomic gain was identified in 18 (41 %) of the liver metastasis tumors, and this frequency of gain was significantly increased as compared to that of the corresponding primary CRCs (11 %) (p = 0.001). Our findings suggested that PRL-3 genomic gain may represent an aggressive phenotype of primary CRC, and may associate with liver metastasis.