Focal loss of CD44 variant protein expression is related to recurrence in superficial bladder carcinoma

The majority of papillary transitional cell carcinomas of the bladder are l ocalized tumors at initial diagnosis; identification of those developing re currence and an aggressive behavior is important. CD44 variant proteins hav e been implicated in tumor progression and metastasis, and a correlation wi th adverse prognosis has been demonstrated in a variety of human tumors. He re, the usefulness of conventional CD44 protein immunohistochemistry as a p rognostic parameter for recurrence of superficial transitional cell carcino mas was assessed in paraffin sections of 241 tumors with long-term follow-u p. A highly significant association was found between focal loss of CD44v3 and -v6 immunostaining and short recurrence-free interval in noninvasive (p Ta) transitional cell carcinomas (P = 0.005), but not in minimally invasive (pT1) carcinomas (P = 0.78). Our results indicate the value of conventiona l CD44 immunohistochemistry as an additional tool for identifying patients at high risk for recurrence of pTa transitional cell carcinomas. They also point to biological differences between noninvasive and minimally invasive transitional cell carcinomas of the bladder.