# Bacterial Therapy of Cancer: A Way to the Dustbin of History or to the Medicine of the Future?
## 2 Bacterial Dualism: What Can Kill Can Also Heal
### Scientists Make Bacterial \"Anti-Cancer Vaccines\" Almost Blindly, and It Sometimes Works! Simultaneously with the search for a \"cancer germ\", the attempts began using microorganisms to treat oncopatients. One of the probably first cases was described in the 1860s by German physician [PERSON], when a patient with a cancer of unknown etiology was intentionally infected by transferring her into a bed in which another patient had died from crysipelas, an infection caused by _Streptococcus pyogenes_. As expected, the patient became infected, and the tumor started to regress; however, the patient soon also died of infection [1, 23, 24]. Other of the most famous in this area were [PERSON]'s experiments of the early 20 th century, who observed that, when patients with sarcomas had acute streptococcal infections, their tumors regressed. He developed a \"vaccine\" (\"[PERSON]'s toxins\") composed of two killed bacterial species, _Streptococcus pyogenes_ and _Serratia marcescens_, to simulate an infection with the accompanying fever without the risk of an actual infection [25, 26, 27]. As a result, prolonged or even complete regression of advanced malignancy was documented in some cases [1, 23, 28]. Moreover, mentioned above, [PERSON] tried to produce an anticancer \"vaccine\" from the _\"Microococcus neoformans\"_ he discovered [17]. [PERSON] also produced an autologous vaccine utilizing her _\"Progenitor cryotocides\"_ organism for the treatment of cancer patients. It was even reported that her husband, who developed a malignant lymphoma of the neck, was healed with the help of this vaccine in six months [15]. Among others, the work of [PERSON] deserves to be mentioned, who microscopically examined the blood of patients with various types of malignant tumors in the 1960s of the 20 th century, and observed some spherical formations (she called them \"globoid bodies\") which were not found in the blood of healthy people. These bodies were located both inside and outside the white blood cells; moreover, their number correlated with the severity of the cancer process. Further experiments with \"globoid bodies\" allowed her to grow on special media some polymorphic microorganism whose etiological linkage with malignant neoplasms was suggested [29, 30]. Similar observations were made around the same time by [PERSON] [31]. Later, this microorganism was identified as a particular species of conrinemorphic bacterium and was named Corinebacterium Krestovnikova-Troitskaya. Based on isolated hemocultures, [PERSON] began the production of anticancer \"autovaccines\", the application of which provided good results in some cases [14]. In 1995, an immunomodulatory pharmaceutical drug on the basis of the Corinebacterium Krestovnikova-Troitskaya strain, which demonstrated a good activity against various types of neoplasms, was patented [32, 33]. The studies mentioned above are just a few of a quite large number of works devoted to the microbiological study of malignant tumors. Unfortunately, neither all nor even most of these works can be covered even briefly in this short retrospective section. In general, the results of these works can be summarized as follows: (1). First, it is a fact that many researchers observed some microbes in human or animal tumors or the blood of cancer patients. These bacteria isolated from tumor tissues were often highly pleomorphic, i.e., they showed a marked degree of morphological variation, one phase of which was often filterable (i.e., able to pass through a submicron membrane filter). (2). The taxonomic affiliation of these microorganisms has often not been established correctly, so now it is difficult to understand what species it belonged to from the point of view of current modern classification. (3). Being injected into animals, these microbes in some cases could cause the development of malignant neoplasms, while in others they did not. (4).