Cell loss and tumor growth revisited

Clinicopathological significance of tissue homeostasis in Indian breast cancer

BACKGROUND

Tissue homeostasis and the maintenance of cell populations depend on a delicate balance between the rates of cell proliferation and cell death. Disruption of this balance is an important factor in development and progression of tumors. In the present study we evaluated the growth index in a large group of breast cancer patients and correlated it with various clinical and histopathological features of the tumor.

METHODS

Estimation of apoptosis was determined by TUNEL assay while immunocytochemistry for proliferating nuclear cell antigen (PCNA) was used as a measure of proliferation. Necrosis was identified morphologically by haematoxylin and eosin staining.

RESULTS

A positive correlation was observed between the percentage of PCNA positive cells and the frequency of mitosis (r=0.6117, p<0.0001). A highly statistical significant correlation was observed between type of tissue analyzed and growth index (r=0.46869, p<0.0001). No significant association was observed between hormone receptor status and growth index.

CONCLUSIONS

The growth index was found to be higher in carcinoma cells that metastasised into lymph nodes compared with primary lesions with no nodal metastasis. Growth index was particularly prominent in high-grade tumors in which increased proliferative activity was evident. Apoptotic cells were detected more frequently in tumor cells with higher rather than lower proliferative activity. This suggests that not only proliferative activity but also capacity for apoptosis is altered in breast tumors.

Fish oil, lipid peroxidation and mammary tumor growth

There is evidence that the level and especially the type of dietary fat can be an important determinant of mammary tumor development and growth. Diets containing high levels of fish oil have been shown to inhibit or suppress mammary tumor growth. Various mechanisms have been proposed to explain this modulatory activity of dietary fish oil or fats in general on tumor growth; of special interest is lipid peroxidation. The oxidation of long chain polyunsaturated fatty acids present in fish oil, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can produce an array of secondary products of lipid oxidation that may possess a cytostatic or cytolytic capacity.

Immunohistochemical analysis of proliferation and differentiation in organotypic cultures of cervical tumor cell lines

Researchers have previously demonstrated that organotypic cultures of cervical tumor cell lines exhibit morphological characteristics similar to the in vivo biopsies from which they were derived (Rader et al., 1990). Both the in vivo biopsy and organotypic culture appeared undifferentiated. We have extended these studies with immunohistochemical analysis using the proliferation and differentiation markers, proliferating cell nuclear antigen (PCNA) and involucrin, respectively, to evaluate in more detail the ability of cervical tumor cell lines to differentiate in organotypic culture. An HPV-immortalized keratinocyte cell line, PE-4, expressed PCNA in the lower half and involucrin in the upper half of the organotypic culture which is consistent with the characteristics of a preneoplastic lesion in vivo. The CC-1 cell line, derived from an invasive squamous cell carcinoma, appeared undifferentiated, but expressed involucrin in the upper half of the organotypic culture. This is the first observation of expression of a differentiation marker in an organotypic culture of a cervical tumor cell line. The other cervical tumor cell lines, SiHa and HeLa, derived from a squamous cell carcinoma, and an adenocarcinoma of the cervix, respectively, did not express detectable levels of involucrin or mucin. All three cervical tumor cell lines, CC-1, SiHa and HeLa, expressed PCNA throughout their entire thickness. The majority of nuclei in SiHa and HeLa cultures were PCNA-positive, while the CC-1 cell line exhibited a lower growth fraction.(ABSTRACT TRUNCATED AT 250 WORDS)