No abstract

Cancer stem cells (CSCs) are a small but critical cell population for cancer biology since they display inherent resistance to standard therapies and give rise to metastases. Despite accruing evidence establishing a link between deregulation of epitranscriptome-related players and tumorigenic process, the role of messenger RNA (mRNA) modifications in the regulation of CSC properties remains poorly understood. Here, we show that the cytoplasmic pool of fat mass and obesity-associated protein (FTO) impedes CSC abilities in colorectal cancer through its N6,2’-O-dimethyladenosine (m6Am) demethylase activity. While m6Am is strategically located next to the m7G-mRNA cap, its biological function is not well understood and has not been addressed in cancer. Low FTO expression in patient-derived cell lines elevates m6Am level in mRNA which results in enhanced in vivo tumorigenicity and chemoresistance. Inhibition of the nuclear m6Am methyltransferase, PCIF1/CAPAM, fully reverses this phenotype, stressing the role of m6Am modification in stem-like properties acquisition. FTO-mediated regulation of m6Am marking constitutes a reversible pathway controlling CSC abilities. Altogether, our findings bring to light the first biological function of the m6Am modification and its potential adverse consequences for colorectal cancer management.

Purpose: Human papillomavirus (HPV) is found in 90% of squamous cell carcinomas of the anal canal (SCCA). We investigated the clinical validity of HPV circulating tumor DNA (ctDNA) detection in patients enrolled in the Epitopes-HPV02 trial that demonstrated the efficacy of docetaxel, cisplatin, and 5-FU as first-line chemotherapy in advanced SCCA.Experimental Design: According to the protocol, serum samples were collected before chemotherapy and on completion of chemotherapy. HPV16 ctDNA was quantified by droplet digital PCR (ddPCR) and correlated with prospectively registered patient characteristics and outcomes. A landmark was set at the time of chemotherapy completion for postchemotherapy progression-free survival (PFS) analyses.Results: Among 57 patients with HPV16-related advanced SCCA, HPV ctDNA was detected in 91.1% (95% confidence interval, 81.1-96.2) of baseline samples. Baseline HPV ctDNA levels were not associated with any patient characteristics; baseline ctDNA level below the cutoff obtained by AUC (area under the curve) was associated with a longer PFS (HR ¼ 2.1; P ¼ 0.04). Among the 36 patients who completed 5 months of chemotherapy, residual HPV ctDNA was detected after chemotherapy in 38.9% of patients. Residual HPV ctDNA detected at chemotherapy completion was associated with shorter postchemotherapy PFS (median PFS 3.4 months vs. not reached; HR ¼ 5.5; P < 0.001) and a reduction of 1-year overall survival rate (OR ¼ 7.0; P ¼ 0.02).Conclusions: This prospective study in advanced SCCA demonstrated a significant prognostic impact of HPV ctDNA level before first-line chemotherapy and HPV ctDNA negativity after chemotherapy completion. With a limited cost and short turnaround, this assay is a promising tool to optimize the therapeutic management of SCCA.See related commentary by Morris, p. 2030

Few specific data exist in the literature on this type of tumor; most of the recommendations come from expert agreements or by analogy with colon cancer. Thus, each case must be discussed within a multidisciplinary team.

Background. Triplet chemotherapy has demonstrated manageable toxicities and a favorable response rate. The addition of cetuximab to chemotherapy can increase treatment efficacy. We evaluated the efficacy and safety of cetuximab plus 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOL-FIRINOX), the ERBIRINOX regimen, as first-line treatment in patients with unresectable metastatic colorectal cancer (mCRC).Patients and Methods. In a phase II study, treatment consisted of weekly cetuximab plus biweekly. Treatment was continued for a maximum of 12 cycles and tumor response was evaluated every four cycles. The primary efficacy criterion was the complete response (CR) rate.