The Laboratory of Pathology of the actual "Professor Ion Chiricută" Oncological Institute of Cluj-Napoca, former "Iuliu Maniu" Institute for Cancer Study and Prophylaxis, had the privilege that in its framework carry on an important part of their activity professors Titu Vasiliu and Rubin Popa, who are forming, beside Victor Babeş, the golden trinity of the Romanian pathology. The Cancer Institute of Cluj, one of the first in the World, was founded in 1929, especially by the clear-sightedness and the efforts of Professor Iuliu Moldovan, the master of the modern Romanian school of hygiene. The clinic division was assisted by a Laboratory of Pathology, whose chief was appointed the young pathologist of high competence, Rubin Popa, associate Professor of this department of the Cluj School of Medicine. In 1942' he became director of the Institute, function accomplished until his premature disappearance in 1958. Titu Vasiliu worked in the Oncological Institute from 1949, a year after his forced retreat from the chair of pathology, up to 1958. Fortunately, his premature disappearance did not interrupt the activity of the laboratory, because the management of the Oncological Institute was committed to Ion Chiricută, an experimented and modern surgeon of Bucharest. From 1960, the Laboratory of Pathology has been led by Professor Augustin Mureşan, an experimented, rigorous and prudent pathologist, who has imprinted these indispensable qualities to his disciples learning under his leadership. The activity of the laboratory has been very favorably influenced by the presence of Professor Gheorghe Badenski from the Department of Microbiology. The collaboration with Professor Eugen Pora from Babeş-Bolyai Department of Animal Physiology and his disciples, Virgil Toma, Draga Nestor, Sena Roşculet, Carmen Stugren and Georgette Buga has carried on the performance of interesting works concerning the thymus involution in tumor-bearing hosts and its signification for the depressed immunity in the advanced stages of cancer. In the same direction, the behavior of mast cells has been studied in collaboration with Professor George Csaba from the Budapest Medical University, Department of Biology. The observations brought about were remarked by the Canadian scientist Hans Selye. Most of these works have been included in the book "Immunity and cancer", distinguished with "Victor Babeş" Prize of the Romanian Academy. The arrival in the Institute of Professor Ion Macavei, disciple of Iuliu Hatieganu and founder of the Clinical Hematology in Cluj, expert in blood and bone marrow cytology, has given a strong impulse to the studies of malignant hemopoietic diseases. The current use of cytologic and histopathologic examinations in this field of pathology and, especially, the introduction by him, for the first time in Romania, of the osteomedullary biopsy has permitted the elaboration of an appreciated work about the cytologic and histologic diagnosis of lymphadenopathies. In the histochemical-histoenzymatic period of the microscopic diagnosis, between the years 1960-1990, the laboratory has enjoyed by the advices and the material help of Professor Raymond Wegmann from the Paris University, Institute of Histochemistry, the founder-editor of the International Review of Histochemistry, from 1976, of Cellular and Molecular Biology, who visited our laboratory in 1992. From 1965, in an adjacent Laboratory of Cytogenetics, Corneliu D. Olinici has performed the first karyotypes in Cluj and has teached the method to several other specialists. Despite the technical difficulties, the works performed in the Laboratory of Pathology have succeeded sometimes to reach the quality required by Professor Chiricută to a valuable scientific work in cancerology. This performance has been obtained by a study concerning Crabtree effect variations in tumoral metastases or about lactic-dehydrogenase behavior in breast carcinomas.