title: Intratumoral hypericin and KTP laser therapy for transplanted squamous cell carcinoma.
abstract: OBJECTIVE
  To test intratumoral photodynamic therapy (IPDT) as a new treatment for squamous cell carcinoma in a preclinical tumor model.
  
  
  METHODS
  Human P3 squamous carcinoma cells were transplanted subcutaneously in athymic nude mice and allowed to grow into 300- to 500-mm3 tumors. Hypericin dye at 1 microg/gm of body weight was injected intratumorally (IT) or intravenously (IV). After 4 hours hypericin biodistribution was assessed in ethanol extracts from tissues by fluorescence spectroscopy. IPDT also was tested by KTP laser fiberoptic insertion in tumors 4 hours after IT dye injection compared to KTP532 laser therapy alone (532 nm, 1W, 40-60 J, 0.6-mm fiber).
  
  
  RESULTS
  Hypericin concentration in tissues was as follows: (IT vs. IV) for tumors (3660 vs. 135 ng dye/gm tissue), lung (760 vs. 6345), liver (75 vs. 935), blood (65 vs. 480) compared to skin (465 vs. 110) or muscle (335 vs. 80) adjacent to the squamous cell tumors. Four hours after dye injection, the tumor exhibited bright orange fluorescence when excited by KTP 532-nm green laser light. The IPDT-treated tumors had a 3.32+/-0.32-mm radius of cell destruction when H&E-stained sections were examined compared with 2.5+/-0.38 mm for the laser only control group (n = 10, P = .003).
  
  
  CONCLUSIONS
  This pilot study indicates laser IPDT with hypericin induces a significant increase in tumor necrosis compared with laser alone and may be useful as a less invasive adjuvant treatment for recurrent or inoperable human squamous cell cancers of the head and neck.
authors.affiliation: Department of Otolaryngology--Head and Neck Surgery, Dankook University College of Medicine, Cheonan, Korea.
authors.forename: P S
authors.initials: PS
authors.lastname: Chung
authors.forename: C K
authors.initials: CK
authors.lastname: Rhee
authors.forename: K H
authors.initials: KH
authors.lastname: Kim
authors.forename: W
authors.initials: W
authors.lastname: Paek
authors.forename: J
authors.initials: J
authors.lastname: Chung
authors.forename: M B
authors.initials: MB
authors.lastname: Paiva
authors.forename: A A
authors.initials: AA
authors.lastname: Eshraghi
authors.forename: D J
authors.initials: DJ
authors.lastname: Castro
authors.forename: R E
authors.initials: RE
authors.lastname: Saxton
mesh_terms: D000818:Animals; D000873:Anthracenes; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000628:therapy*; D015552:Injections, Intralesional; D053685:Laser Therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010569:Perylene / Q000008:administration & dosage / Q000031:analogs & derivatives*; D010778:Photochemotherapy; D010865:Pilot Projects; D014407:Tumor Cells, Cultured
chemical_list: D000873:Anthracenes; D000970:Antineoplastic Agents; D010569:Perylene; C004965:hypericin