The present invention relates to a method of inhibiting carcinoma progression wherein matriptase plays a role in a subject in need of such inhibition including administering to a subject an effective amount of a compound comprising two positively charged groups, which are the same or different. The groups are linked by a chemical group having a length of between 5 and 30 A, and preferably between 15 and 24 A. Diagnostic methods based on matriptase action and therapeutic methods involving inhibition of matriptase activity are provided.