FCM has until recently been predominantly used to phenotype leukemias and lymphomas and to aid in prognosis of nonhematologic tumors.

Nonhematologic tumors

In nonhematologic tumors, predominately aneuploid neoplasms (especially if the S-phase value is increased) generally are more aggressive and have shorter survival time than tumors that are predominantly diploid and have normal S-phase values. However, this varies considerably between different tumor types, and there is often variation between tumors in different patients with the same tumor type. Added to this are various technical problems, such as mixtures of diploid and aneuploid tumor cells, mixtures of normal cells and tumor cells, differences in degree of tumor anaplasia in different areas, whether the tissue is fresh or formalin-fixed, proper adjustment of the instrumentation, and experience in avoiding or interpreting variant DNA peaks. S-phase work in nonhematologic tumors is more difficult than standard ploidy determination and sometimes cannot be done adequately.

The most intensively studied (or reported) nonhematologic malignancies have been breast, colorectal, prostate, urinary bladder, ovary, and uterus.

In breast carcinoma, there has been considerable disagreement between various studies, but overall suggestion that DNA ploidy is not a reliable independent factor in predicting likelihood of lymph node metastasis or length of survival. S-phase analysis is much more difficult to perform adequately but appears to have some predictive value regarding lymph node metastasis, degree of tumor differentiation, and presence of estrogen receptors. In colorectal cancer, the majority of studies have found that aneuploid tumors usually have shorter survival than diploid tumors and there is some correlation with probable Duke’s tumor stage (except for stage D) and therefore overall survival. In early superficial (noninvasive) transitional cell carcinoma of the urinary bladder, degree of aneuploidy has predictive value for invasiveness and tumor grade. FCM on bladder washings has additive value to biopsy of early superficial lesions. If the DNA index (measuring aneuploidy) of the biopsy differs from that of bladder washings before treatment, this suggests higher risk of tumor invasion. If the bladder washing DNA index is aneuploid and that of the biopsy is diploid, this suggests carcinoma in situ. However, if both are aneuploid, there is no prognostic assistance. Bladder washing FCM is considered the best test to follow up a patient after tumor surgery. If intravesical chemotherapy is given, it is necessary to wait 6 months after the last chemotherapy dose to resume bladder washing surveillance (because of chemotherapy-induced abnormalities in normal epithelial cells). Fresh urine specimens are much better than preserved specimens; the fresh specimen should be refrigerated immediately and analyzed as soon as possible, but no more than 12 hours later. If that is not possible, appropriate fixative must be added. In prostate carcinoma, DNA diploid tumors tend to be better differentiated (lower grade), respond better to radiation therapy, and have longer survival time; aneuploid tumors tend to be less differentiated (higher grade) with a worse prognosis and usually have less response to estrogen therapy. In ovarian carcinoma, diploid carcinomas in stage III or less have a much better prognosis than aneuploid carcinomas. In melanoma and in renal, endometrial, bone and cervix carcinomas, diploid state has some chance of a better prognosis.

Hematopoietic malignancies

In hematopoietic malignancies, malignant lymphomas that are diploid are usually lower grade and less aggressive, with the opposite generally true for aneuploid lymphomas. However, not all reports agree. S-phase analysis is also said to have prognostic value. Burkitt’s lymphoma has an interesting FCM profile, since it is usually diploid but has a high S-phase value and behaves like a typical aneuploid tumor. Childhood acute lymphocytic leukemia (ALL) that is aneuploid has a better response to chemotherapy. This has not been shown with adult ALL or with acute myelogenous leukemia.