Abstract
When laminin, a constituent of the basement membrane, was used for the evaluation of neural invasion in rectal cancers, reliable results were obtained. Laminin staining was very useful for the evaluation of neural invasion, because staining of the perineurium and nerve fascicles was more distinct than that of other staining methods, including hematoxylin-eosin, silver-impregnation and S-100. The incidence of positive neural invasion in laminin staining was 47.8%. Moreover, neural invasion was strongly correlated with the depth of invasion, venous invasion and lymph node metastasis. Local recurrence was found in 16.6% (26/157) of the cases. A significantly higher frequency of local recurrence (26.7%) was observed in neural invasion positive cases, compared with neural invasion negative cases (7.3%). The 7-year survival rate for neural invasion negative cases (77%) was significantly higher than that for neural invasion positive cases (39%). Neural invasion may be an important prognostic factor which influences both recurrence and the survival rate, particularly in cases of cancer cell infiltration into the perineurium. Using laminin staining, the evaluation of neural invasion may be useful in the determination of pre- and postoperative adjuvant therapy as well as indication of autonomic nerve preserving operation
