Droplet digital PCR detects high rate of TP53 R249S mutants in cell-free DNA of middle African patients with hepatocellular carcinoma

Agnès Marchio (1) , Marie Amougou Atsama (2) , Aubin Béré (3) , Narcisse-Patrice Komas (3) , Dominique Noah Noah (4) , Paul Jean Adrien Atangana (2) , Serge-Magloire Camengo-Police (5) , Richard Njouom (2) , Claudine Bekondi (3) , Pascal Pineau (1)

1 Organisation Nucléaire et Oncogenèse / Nuclear Organization and Oncogenesis
2 Centre Pasteur du Cameroun
3 Institut Pasteur de Bangui
4 Hôpital Central de Yaoundé
5 Hôpital de l'Amitié [Bangui]

Hepatocellular carcinoma (HCC) is still a major killing malignancy in sub-Saharan Africa. Lifelong intoxication with aflatoxin B1 is considered as one of the primary causes of this situation. The role of aflatoxin in HCC from a given population is commonly estimated through the prevalence of R249S mutation of TP53, a hallmark for previous exposure to the mycotoxin. However, the role of AFB1 is barely known in large part of Africa. We conducted a survey on circulating cell-free DNA from 149 patients with HCC and 213 control subjects with and without liver diseases from Cameroon and Central African Republic using droplet digital PCR technique. We observed a mutation prevalence of 24.8% (n = 37/149) in patients with tumor and 5.6% (n = 12/213) in controls (P = 2.2E-07). Patients with mutations usually displayed significantly increased circulating alpha-fetoprotein (AFP) values, high hepatitis B virus (HBV) DNA loads as well as worsened values of blood cells count. Interestingly, the fraction of droplets positive for R249S was significantly larger in patients with liver cancer (15.3 ± 3.7%) than in controls (0.5 ± 0.3%, P = 7.1E-04). Our survey indicates that AFB1 is instrumental for HCC development in Middle Africa and that droplet digital PCR might be used in the region both to diagnose HCC and to conduct public health surveys on populations at risk of chronic aflatoxin intoxication.

Mots clés: TP53 mutants; Hepatocellular carcinoma; Droplet digital PCR; Cell-free DNA

Domaines: Cancer

Agnès Marchio, Marie Amougou Atsama, Aubin Béré, Narcisse-Patrice Komas, Dominique Noah Noah, et al.. Droplet digital PCR detects high rate of TP53 R249S mutants in cell-free DNA of middle African patients with hepatocellular carcinoma. Clinical and Experimental Medicine, 2018, 18 (3), pp.421-431. ⟨10.1007/s10238-018-0502-9⟩. ⟨pasteur-02611946⟩