Potential of miR-21 to Predict Incomplete Response to Chemoradiotherapy in Rectal Adenocarcinoma

Background: Patients with locally advanced rectal adenocarcinoma (LARC) are treated with neoadjuvant chemoradiotherapy (CRT). However, biomarkers for patient selection are lacking, and the association between miRNA expression and treatment response and oncological outcomes is unclear.

Objectives: To investigate miRNAs as predictors of response to neoadjuvant CRT and its association with oncological outcomes.

Methods: This retrospective study analyzed miRNA expression (miR-16, miR-21, miR-135b, miR-145, and miR-335) in pre- and post-chemoradiation rectal adenocarcinoma tissue and non-neoplastic mucosa in 91 patients treated with neoadjuvant CRT (50.4 Gy) and proctectomy. Two groups were defined: a pathological complete responders group (tumor regression grade—TRG 0) and a pathological incomplete responders group (TRG 1, 2, and 3).

Results: miR-21 and miR-135b were upregulated in tumor tissue of incomplete responders comparing with non-neoplastic tissue (p = 0.008 and p < 0.0001, respectively). Multivariate analysis showed significant association between miR-21 in pre-CRT tumor tissue and response, with a 3.67 odds ratio (OR) of incomplete response in patients with higher miR-21 levels (p = 0.04). Although with no significance, patients treated with 5-fluorouracil (5-FU) presented reduced odds of incomplete response compared with those treated with capecitabine (OR = 0.19; 95% confidence interval (CI) 0.03–1.12, p = 0.05). Moreover, significant differences were seen in overall survival (OS) in relation to clinical TNM stage (p = 0.0004), cT (p = 0.0001), presence of distant disease (p = 0.002), mesorectal tumor deposits (p = 0.003), and tumor regression grade (p = 0.04).

Conclusion: miR-21 may predict response to CRT in rectal cancer (RC).

Time course of serum C-reactive protein levels during induction chemoradiotherapy and its correlation with treatment response and survival in patients with advanced esophageal squamous cell carcinoma

Preoperative serum C-reactive protein (CRP) levels have been shown to be of prognostic significance in patients with advanced esophageal carcinoma. However, the clinical significance of serum CRP levels in patients with unresectable or marginally resectable tumors in the absence of induction therapy has not been fully elucidated in relation to treatment response and prognosis. Thirty-four patients with clinical T3-T4 esophageal squamous cell carcinoma who underwent induction chemoradiotherapy (CRT) followed by esophagectomy were enrolled in this retrospective study. Serum CRP levels were measured during the course of CRT, i.e., prior to, during (1, 2, 3 and 4 weeks following initiation) and after CRT (prior to surgery). The association between CRP levels, CRT response and survival was analyzed. Elevated serum CRP levels exhibited a favorable decrease 2-3 weeks following CRT initiation in pathological responders and CRP ≤0.3 mg/dl at 2 and 3 weeks following CRT initiation, as well as prior to surgery, was significantly correlated with responders. In patients with pretreatment CRP >0.3 mg/dl (67.6% of patients in this study), CRP ≤0.3 mg/dl at 2 and 3 weeks following CRT initiation predicted responders with accuracies of 87.0 and 73.9%, respectively. In the univariate survival analysis, CRP levels 3 weeks following CRT initiation, as well as CRP levels prior to surgery and pathological stage, were significant prognostic factors, although CRP levels prior to surgery was the only independent prognostic factor in the multivariate analysis. Serum CRP levels during the course of CRT may be of prognostic and predictive significance for the CRT response in patients with unresectable or marginally resectable esophageal squamous cell carcinoma who undergo induction CRT.