Dr. Tanaka was a character in Alien: Sea of Sorrows.
Dr. Tanaka and her team were investigating the silicon black tubes that sprung up out of the Sea of Sorrows, later Tanaka and her team were captured by the Xenomorphs and cocooned. Tanaka was discovered by Mannin's team alive but already impregnated. Tanaka was mercy killed by Mannin but not before telling the group about the Xenomorph's numerical superiority and tried to tell them about the Queen.
Tanaka's fate is not alluded to in the novel, she is merely mentioned by Rollins as someone who doesn't exaggerate, when considering her report.