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Formalin is commonly thought to decrease the risk of Mycobacterium tuberculosis infection. However, the true disinfection efficacy of formalin for tissue infected with M tuberculosis is unclear. We reviewed all pertinent literature from 1900 until the present regarding the disinfection efficacy of formalin for tissue infected with M tuberculosis. We also retrospectively cultured five cases of M tuberculosis from formalin-fixed archival pulmonary tissue. All cultures from our archived tissue were negative. The literature review revealed limited and contradictory information concerning the viability of M tuberculosis in formalin-fixed human tissue. There are no studies which specifically address the viability of M tuberculosis in tissue exclusively fixed in 10% buffered formalin. The disinfection efficacy of formalin for tuberculosis infected tissue remains unclear. Larger, prospective studies using current methodologies are needed to establish guidelines to ensure the safety for those handling infected, fixed tissue.

Abnormal expression of p53, transforming growth factor alpha (TGF alpha), epidermal growth factor receptor (EGFR), and c-erbB-2 occurs in a variety of cancers and in some cases is associated with poor prognosis. Immunoperoxidase staining using these markers in formalin-fixed, paraffin-embedded endometrial carcinoma tissue was performed to determine whether immunoreactivity correlates with survival and known prognostic variables. Cases included 84 endometrioid adenocarcinomas, five adenoacanthomas, 12 adenosquamous carcinomas, 11 serous carcinomas, 15 clear cell carcinomas, and one carcinosarcoma for a total of 128 cases. Frequencies of immunoreactivity were as follows: p53, 37 of 128 (29%); TGF alpha, strong (2+) 23 of 128 (18%) and intermediate (1+) 26 of 128 (20%); EGFR, strong (3+) 21 of 128 (16%) and intermediate (2+ or 1+) 83 of 128 (65%); and c-erbB-2, strong (2+) four of 128 (2%) and intermediate (1+) three of 128 (1%). p53 and TGF alpha staining showed statistically significant correlations with decreased length of survival (P < .0017 and P < .0013, respectively, generalized Savage [Mantel Cox]). p53 immunoreactivity correlated with tumor types, grade, and stage. Transforming growth factor alpha staining correlated with increased depth of invasion and presence of vascular invasion. Epidermal growth factor receptor staining did not correlate with length of survival or known prognostic variables. c-erbB-2 staining correlated with tumor type. In the multivariate analysis p53 and TGF alpha staining were not independent predictors of survival when other variables were taken into account, including grade, stage, tumor type, presence of vascular invasion, and depth of invasion. Grade and stage were the only independent predictors of survival when used in combination in a Cox proportional hazards model.