Question: who was kat slater's sisters in eastenders?
Answer: Lynne, Little Mo, Zoe

Lynne is the eldest of the Slater sisters and she arrives in Albert Square in 2000 with her family: father Charlie (Derek Martin); sisters Kat (Jessie Wallace), Little Mo (Kacey Ainsworth) and Zoe (Michelle Ryan), and grandmother Mo (Laila Morse). Unlike Little Mo and Zoe, Lynne is aware that Zoe is in fact Kat's daughter and helps keep the family secret until Kat reveals the truth to Zoe.