Within the C-HPP, the French and Swiss teams are responsible for the annotation of proteins from chromosomes 14 and 2, respectively. neXtProt currently reports 1231 entries on chromosome 2 and 624 entries on chromosome 14; of these, 134 and 93 entries are still not experimentally validated and are thus considered as "missing proteins" (PE2-4), respectively. Among these entries, some may never be validated by conventional MS/MS approaches because of incompatible biochemical features. Others have already been validated, but are still awaiting annotation. Based on information retrieved from the literature and from three of the main C-HPP resources (Human Protein Atlas, Peptide Atlas and neXtProt), a subset of 40 theoretically detectable missing proteins (15 on chromosome 14 and 25 on chromosome 2) was defined for upcoming targeted studies in sperm samples. This list is proposed as a roadmap for the French and Swiss teams in the near future.