Jan started her career as assistant of Sixto Valencia, one of the most prominent comic book artists in Mexico. For over two decades, she worked in almost every genre in Mexican comic books including action, comedy, horror, western, detective, romance, and wrestling stories, penciling over 3,000 covers. Jan brought her hyperkinetic art style to SPIDER-MAN for a star-marking run as the young Miles Morales took on the all-new Sinister Six in SPIDER-MAN #234–239. She burnished her reputation with titles including MR. AND MRS. X and LOKI, and her fast-growing list of Marvel credits now includes X-FORCE, WINTER GUARD, and a trip to the far-off galaxy of STAR WARS.